EU4 - Development Diary - 26th of March 2019

[RobRoy3]

Frankly, I fear your "fixes" for mercenaries.

Based on your recent "fixes" for conversion, territories, end-game tags, etc., the potential for degrading the game is high.

Of course, none of those things required fixes, in the first place. And mercenaries have been crying for a "fix" for years.

But I would much prefer you fix the (unintended?) consequences of recent "fixes", first. If I can play a game without seeing a pagan Mexico, various Sunni colonies, and a stagnant religious map throughout the world, then maybe I can get excited about potential fixes to mercenaries.

 

[Canute VII]

Since we're talking mercs, can we also talk condottierri?

View attachment 465885

Why is a country with a perfectly good coast, rejecting help from a country with a strong navy? It makes even less sense once one considers that military access is obtainable by default. Also even when I have direct military access to their capital, I can't offer them. Why was this system even added to the game if it is only meant to be used with neighbors that aren't rivals?

Also, why not combine the mercenary system and condottierri system into one consistent system? There can be AI companies from which one can recruit to supplement their armies as well as condottierri from existing countries.

Exactly... I see no reason why your England shouldn't be allowed to send condottieri, provided they have enough transport ships (equal the size of the condottieri army).

Sure, one could say, this was exploktable: offer condottieri, get paid, do not fear the enemy comes over cause, you know, AI. But war participation is a thing, so if you exploit, then it will likely be the first and also the last time, since afterwards no country will trust you anymore.

It could even be made, that your condottieri army be auto-transported to the hiring country's capitsl, only after it arrives, you get control over it back.

 

[Azgabeth]

I think mercs should change as the ages change, although I don't have the best idea of how this should work.
Personally I would like the mercenary companies to be represented in some way. (I know they were fading out of use by the start of the game, but some were still present)
I'm thinking having a tab of available Special companies with their own names, i.e.: White Company, Company of the Rose and each has their own special boost, say: +10% Infatry Shock, +15 Cavalry flanking. Of course this companies should be more expensive then normal mercs, but the their bonuses should make up for that.
I also think this companies should have rivalries between each other, ex.: "White Company" is rival with "Company of the Rose" this would then ensure that ONE country doesn't take all the companies at once when at war since rival companies would prefer to fight each other rather than on the same side.

I'm also thinking perhaps a building should be acquired around tech 9~11 ish which would propagate an increase in manpower pool of the country, the chance for a company to form in that region, and the quality of the mercs.
Honestly I don't know how historically accurate these ideas are but i'd still like to share them.

 

[RaptorCommander]

Manpower recovery should be higher in peace then it is now. So that the game doesnt need mercs as much to remain 'fun'.

Prehaps war exhaustion should decrease manpower recovery?

 

[Steel_atlas]

Exactly... I see no reason why your England shouldn't be allowed to send condottieri, provided they have enough transport ships (equal the size of the condottieri army).

Sure, one could say, this was exploktable: offer condottieri, get paid, do not fear the enemy comes over cause, you know, AI. But war participation is a thing, so if you exploit, then it will likely be the first and also the last time, since afterwards no country will trust you anymore.

It could even be made, that your condottieri army be auto-transported to the hiring country's capitsl, only after it arrives, you get control over it back.

Now that you say it, something akin to what imperator where mercenary armies are represented on map and would function as easy to use Condottiete

 

[purplephoton]

Prehaps war exhaustion should decrease manpower recovery?

It does already though.

 

[Pellucid]

I think mercs should change as the ages change, although I don't have the best idea of how this should work.

Just give them tags like any country. Track their stats differently; maybe update them yearly instead of monthly to cut down on CPU drain. Give them numerical values for:

Budget: Affecting how good their troops are; increases the effect of any combat modifiers they have. Is changed by how profitable their recent existence has been; increased by being hired, decreased by long periods without being hired.
Manpower: Affected negatively by recent losses or long periods with a poor budget value; affected positively by countries in their home regions disbanding armies, by stackwipes in their home regions, and by countries in their home region being annexed. Should have a maximum value (perhaps 2 times their army's field strength). This manpower pool would be the source of their re-enforcements. If it's at 0, they don't re-enforce.
Size: How many units and of which types they have. A mercenary army with a strong budget would "buy" more units with that budget. This would decrease their current budget but give them an opportunity for long-term growth. A mercenary army with a weak budget would disband troops back into their manpower pool and shrink.

If their size reaches a set minimum (6, perhaps?) and their budget hits zero while they're already at that minimum, remove them from the merc pool. Add new mercs to the pool over time anytime the available number of mercenary armies in a region is low.

This could be an entire sub-economy. As I said, update it per year instead of per month and it won't drain CPU too much, and it would feel really dynamic and satisfying.

EDIT: Oh, and of course remove mercenary companies from the pool if they get stackwiped and don't have any manpower left to re-enforce.

 

[wkscrombie]

As others have said, I’d really like to see a sort of supply chain mechanic implemented (to make attrition really matter, as it did historically)— upgradable roads would be a great step in that direction (which could also influence army speed, something which should have more variance, especially when in your own versus in an enemy’s territory), as would naval supply lines (which would help navies actually matter for tags other than England/UK and Japan).

With regards to mercenaries, I haven’t played or paid much attention to Imperator, but I think something similar to the CK2 system would be a massive improvement. Tie availability, cost, and effectiveness to the age system or military technology to simulate their decline in relevance (just an idea— maybe, beginning in the Age of Absolutism, have a -.5 diplomatic reputation malus per currently hired company, and increase that to -1 in the Age of Revolutions). Also, I agree with many others that mercenaries/mercenary companies from different regions should have significant differences in composition, traditions.

Thanks for your consultation of the community. And Portugal needs updated ideas.

 

[CollapsingHrungDisaster]

The key problem is with armies themselves.

Right now armies are ahistorical - they aren't "standing armies", but rather simplified versions of modern regular armies. Which is fine for a game, but only up to some point.

Point is, armies should become less regular:

• There should be core standing army, always maintained; expensive to keep, thus used as a core unit, but having more powerful units - one of the examples would be Janissaries
• Cavalry and artillery should always be a maintained standing army
• Main bulk of army, infantry essentially, should be ""mobilized"" aka just banded together for a war, having lower military stats and kinda being canon fodder
• This changes over time and by increasing army tradition, doing military reforms and such, you will in the end achieve the modern regular army;
• Thus, manpower bleeds soldiers which are mainly prepared for a war (and should be easier to prepare and maintain); standing army would bleed less, be a core to your troops (artillery and cavalry especially)
• Drilling becomes a way to turn yesterday's peasants recruited into army into good soldiers, being critically important;
• War maintanence is no longer ad sliceable: you maintain standing army fully and bigger mass of recruited army only at war (and not as costly as standing army as they traditionally required less pay)
• Underpaying standing army could result in a palace coup or other revolt

But what about mercenaries?

• Mercenaries become a standing army replacement - temporary hired to boost your core army, like add artillery, to not keep standing army all the time
• Merc system could follow CK2, but with only limit - attaching mercs to certain armies and sending them there instead of spawning in capital
• Condottiere could be integrated into it? Or at least give an option to allow to send some soldiers into merc mode, bringing you income.

Standing armies would change balance. They would empower economically powerful nations that could maintain standing armies, Ottomans and Hordes. However, small nations could still have enough power/coalitions to fight off. And these armies could also be a challenge to stability - like in case with Janissaries. So, perfectly the best way to deal with army would be having plenty of army tradition and other military buffs.
Naturally, corruption could reduce army tradition. Although, I would change corruption first before that.

One could also consider having standing and recruited armies as "mothballing" armies - and it would be a correct thing to do.
Recruiting army for a war wouldn't require to click there. You could make state interface and rally points per state. For example, like historically setting Stambul as a rally point for Ottomans before going to Vienna.

Mercs would definitely benefit from this. They would stop being a cannon fodder (which they weren't) and become a relevant "elite", which is needed to make up for lack of disciplined corps, artillery, add more core to your army so it wouldn't turn around running and so on.

In short, yes, it is closer to retinue and "summonable army" of CK2. But I believe it would make armies way better, as well as make mercs matter.

To jump on this idea: a common theme in EU4s time period is the crippling cost of large-scale warfare. Most famously, funding the Seven Years' War was sufficiently costly to Britain to lead to taxation changes that prompted the American Revolution, and the huge cost of helping to fund that revolution gave France one of her own. War was hugely expensive: a major power in EU4 should (historically) not be emerging from a major war without being in some quite substantial debt, and arguably shouldn't be able to fund wide-reaching military ventures without colossal economic power to back it up. As the OP has suggested, this happened historically because elite standing armies were supplemented by wartime drafted regiments, who were usually laid off at the war's end as their huge cost could not be justified (inevitably leading to huge increases in rural poverty and violent crime, most notably in the instance of Caribbean piracy following the War of Spanish Succession). Hell, England didn't really have a home standing army at all from the mid-16th century up until the Civil War, relying instead on its navy and colonial troops.

A simple way of coming close to implementing this, in my view, would be to make troops much cheaper to recruit but more expensive to maintain, and either doing away with or severely modifying the concept of a force limit (which generally encourages players to build and maintain their maximum capacity constantly). This, in combination with a shot to the arm for the drilling/professionalism system could incentivise players to raise large proportions of their armies (and, in particular, mercenaries) only when they needed them, and employing only a small, well-drilled full-time army to act as a deterrent/colonial police/hardcore Space Marines batallion the rest of the time.

(also, consider this one more for the "supply trains please ohgodyesitwouldmakefortsmakesenseagain" faction!)

 

[Toodguy]

What if mercenaries, instead of having a certain amount available for each nation, had a certain amount available for a region? Say mercenary units were based out of certain provinces on the map, and any nation close enough could hire out those mercenaries.

This way, nations like venice or genoa who have little manpower but tons of money could hire out mercenaries from all over europe and maybe north africa, but if say france, england, and austria all tried to mercspam, there wouldnt be enough mercenaries available between the three of them.

You could make the cost and maintenance of mercenaries scale towards how many are being used nearby, also. If someone hires a bunch of mersenaries in Saxony, for example, nearby Bavarian mercenaries may charge more.

 

[Balesir]

This sounds great, but for me, the thing that needs to be introduced into EUIV warfare mechanisms is some sort of notion of supply train, to stop the ludicrous game of "chase the fuck-off stack" around the map. An example of how it could be implemented would be if your army is in a province that is not connected to your capital, through your own provinces, occupations, or transport ships nearby, that army should be taking massive attrition and have a massive speed penalty!

I would very much like for roads to play a part in the supply game.

The problem I have with both of these is that supply in this period really didn't work that way. Prior to 1914, armies did not get their supplies sent from the homeland - they arranged purchases/looting/shipping locally from the markets in the area - the people living there almost always outnumbered the army by a good margin, so food was available in the required quantity unless the local population were starving.

If you want a good (and realistic) incentive based on supply, it should be that really large armies should be forced to move. Getting food for a small force could be easy - just buy from the market - but for big armies the supply dwindles over time. Maybe make getting near to the supply cap cause the supply cap to decrease on a sliding scale over time? This becomes especially problematic with sieges; this was the one time that supply trains were actually used. Maybe have "train" units that can spread the supply load over adjacent provinces, treating the force as though it is divided among all adjacent provinces that don't contain and are not adjacent to enemy troops, and aren't in enemy fortification ZOCs?

The one place that connection to the capital comes in is what was called "lines of communication". This didn't have anything really to do with supply, but it was how news, instructions and reinforcements were provided. Maybe lack of connection to home territory means no reinforcement, and lack of a connection to the capital means a reduced morale (similar to when underpaid)?

I would personally really like a mercenary manpower pool per region (France, Iberia etc).

Some battlefield losses from regular manpower could also contribute to the mercenary manpower pool, what with desertions and such.

This idea definitely has legs. Cultural manpower pools, replenished at a slow rate normally, but with disbanded regiments contributuing heavily and general casualties contributing a bit, would be nice. Units of your own culture could benefit quickly from national ideas etc., those of other cultures less so. Mustering point could be any province of the appropriate culture.

 

[Canute VII]

The European Expansion and its update will, in all likelihood, feature a completely different mercenary mechanic from what we know today. We have established several key aspects of how we want to handle mercenaries:

1. We still want them to exist as a way to supplement one's army strength for ducats.
2. Province-level recruitment will probably have to go. Reducing click-fatigue while we're at it should be a priority.
3. The system should respect geopolitics: Mercs in India should be functionally different from Germanic ones.
4. Mercs must be finite to some degree. As an example, a prolonged 30 years war should drain Central Europe of available mercenaries, and said merc units should find themselves no longer able to reinforce.
5. Player involvement in the system must be greater than it is today
6. Late game multiplayer must be diversified from all out merc-on-merc warfare.
7. The system should be robust, feel alive, and enjoyable

Well, I guess you have already consulted the suggestion subforum? There have been a few suggestions on merceneries (that I'm not going to repeat here and now).

Anyway, these are some thoughts I had while reading this thread. Maybe they can be useful.

• make a new spy action, which -if successful- let's you choose a number of mercs from that foreign country. These mercs would be of that country's tech group and (maybe) come with that country's army modifiers. Their number would be restricted to that country's free force limit, i.e. you can't get mercs from a county which already operates at full force limit. Maybe, if it operates at full force limit and has mercs of its own, then you can "steal" some of its mercs. The mercs would emerge in the foreign country's capital, be black-flagged and move to the nearest of your provinces, only then you get control over them. Obviously, the farer away the country the longer the waiting. Or, alternatively, you need to have mil access to that country. This would satisfy your condition (2) and (3).
• make mercs increase military technology cost and/or mil idea cost (or just, you know, all mil power cost), scaling by number of mercs to force limit. This would represent the limited control over them and that it requires additional effort to make them comply. Hence, only countries with high mil point income would be able to constantly field a merc army without falling behind on army quality. It could also mean that certain actions like "bombard fort" etc. can only be taken less often than while fielding a no-merc army. And see how early aristocratic ideas get indirectly buffed (but not late arist. ideas). Alternatively, why not have a stability cost increase like for streltsy? Anyway, point to be taken is: there should be a cost other than ducats.
• split all the military combat modifiers in "regular" and "mercenary" ones. E.g. have "+5% regular discipline" and "+5% mercenary discipline" instead of "+5% discipline". Then reallocate these modifiers so it makes sense....
• make merc reinforement rate dependent on local devastation: the more devastation in a province, the less or slower mercs reinforce. This would satisfy your condition (4).
• make cavalry more relevant and somehow restrict "full backrow artillery" - this would likely also help with the "full frontrow merc infantry". E.g. cavalry could be ordered to try and break through the front line / bypass it at the sides to bring havoc to the enemy artillery, a bit like "fort assault" works, maybe?

 

[klingonadmiral]

Here's my two big issues with mercenaries:

1. They don't come from anywhere.
2. They apparently aren't people because they don't need people to reinforce themselves.

So, how to solve this?

In my opinion land units should be divided into three separate categories:

1. State Troops, aka non-mercs
2. Raised Mercenaries, who are working for the country that raised them and haven't been hired by anyone else yet
3. Hired Mercenaries, who are either working for a country that hasn't raised them or are working for the country that has raised them but had previously worked for another country

To explain how this works, let's take 1444 France as an example. Currently they enjoy a force limit of 38. I would split it in a State Troops FL of 30 and a Raised Mercs FL of 10. So France can build 30 regiments of normal regiments and 10 regiments of mercs before maluses begin to apply (and I would severely ramp up the maluses for going over FL). Raised Mercenaries could maybe have a pip more than State Troops or perhaps a morale/discipline/combat ability bonus, but they come with a significant downside: After a certain amount of years, they can either be sold off to someone else or hired away. So if our hypothetical France is relying heavily on Raised Mercs and is currently fighting say Austria and the HRE gang, if the Habsburgs can pay the price a good chunk of their army might defect a day before a pitched battle and instead join their former enemies. You could, of course, disband and re-build Raised Mercenaries when they are about to become able to defect, but then you are wasting a good chunk of manpower and money just to keep up your army. Or perhaps you can buy a few years of extended loyalty for a lump sum of cash. Especially during periods of peace or while you are warring with someone poor you might want to let your regiments go however as you would get some cash back and those regiments would then become Hired Mercenaries. Hiring enemy mercs however should be limited to to only work an adjacent regions, lest you could get issues when half the Spanish Army in Iberia defects to the Inca.

Hired Mercenaries would then have the following attributes:

• they don't count towards either force limit
• they have increased upkeep compared to State Troops, but in return accrue no additional cost when reinforcing
• reinforcing Hired Mercs costs manpower
• after a certain period (5-10 years maybe) they can once more be re-hired by someone else
• they cannot be disbanded or consolidated

This would more or less reverse the current purpose of mercenaries. Instead of becoming a way for rich countries to stretch out wars to nigh-infinity, they would turn into force multipliers during pitched wars. Persia might not be able to 1v1 to Ottomans, but Persia that has hired 50 Mercenary regiments might. But be wary of walking into a meatgrinder war while running mercenaries. They might still be good at absorbing losses, but they would burn through your manpower just as fast as any other unit, and if you run a full FL army parallel to your mercs.

But ... perhaps there is a way to have your wars fuel themselves. After all, if you can't make a profit during war, you can't make a profit. See, those people in that city that the enemy calls his own have nice things, and a few of those lads would also make fine soldiers. So why not force them to relinquish their treasures and sons? In times of peace you would call such things murder and robbery, but isn't war just a fancy name we gave to large-scale murder and robbery?

Less flowery, looting has to be massively reworked. The current "look, this bar ticks down and you get money while it does" thing is simply unable to portray the reality of such a process - especially when a very similar thing already exists in the game in the form of Hordes being able to raze provinces. So, why not give all units the ability to properly reduce a province's development in exchange for money and manpower? If there once was a fear that such a feature would turn the world into a barren desert for those that didn't own Common Sense, as increasing development is now a free feature this should no longer be of any worry.

Oh, and we maybe should get rid of the myth that the prevalance of mercenaries ended with the Peace of Westphalia. There was a trend that mercenaries became more "one-sided", hired by the few great powers of Europe from various minor polities (Scotland, Ireland, the HRE), but they nonetheless remained an integral part of any serious army. Only with the rise of the nation-state in the early 19th century did the era of mercenaries truly end.

Finally, some more unsorted thoughts:

• you can't rework mercenaries without reworking loans, and you can't rework loans without reworking mercenaries. One feeds off the other - take loans to hire more mercenaries to conquer more land to take more loans to hire more mercenaries to conquer more land and so on and so forth until 1821 or WC is reached
• it may also be neat to allow regiments to "over-reinforce" during peacetime (would be especially useful when forced into a regency), essentially swelling up to 2,000 men (but still only 1000 combatants) to fully reinforce for free once the next month ticks over.

 

[FurorGermanicus]

Played my last multiplayer match last year, until 1500 I had over 3k ducats with Aragon. But what could I do, spend them on buildings that provide tiny bonuses? Of course not, I hired mercs instead!

 

[Krullevaar]

I never use mercenaries in EU4 because they're too expensive and I'm always struggling with the economy/trade part of the game. I would consider using them if they would be considerably better than regular units. Also, they should be different in name, appearance and function (=have a special ability?), based on the area where you hire them. For example: Landsknechte, Swiss guards, stradioti, hussars, cossacks, askari, native American scouts and of course the famous ghurkas. Some countries that relied heavily on mercenaries, like the Dutch republic, should get some kind of national bonus to make mercenaries cheaper for them. And France should get a "foreign legion" bonus.

Also, I like Stratagyfan101's idea to combine mercenaries and condottieri into a single system. Quoting didn't work but he wrote it a couple of pages back.

 

[Chief of Staff]

Will regiment sizes be changed? 1,000 man artillery unit is a bit unrealistic and having a regiment of 1,000 fit in a boat is even less. Company size of 250 might be more appropriate.

Most mercenaries were veterans from previously fought wars.

What if dissolving experienced regiments makes those regiments go into the mercenary pool instead of going back to the "farmer life"?

I am a bit unclear on what you meant by that. Are you proposing setting all regiments to company size of 250? That could be a micro-management nightmare, considering we constantly shuffles the regiments between armies and such.

But I wouldn't mind seeing deeper organization, though, with company being a component of the regiment but I can't think of any gameplay function that would serve, just like the brigade. Unless we find any purposes or functions for these unit sizes other than regiments and army (or stacks as we like to call them), having other levels of the unit represented would be pointless. I would have advocated division as well but that only came into being by Napoleonic era unless there is a way to introduce a new level onto the military organization somehow. Brigade were introduced in Thirty Years' War by the ruler of your truly, Sweden. Also, it should be noted that there is in fact a level between company and regiment which is battalion.

Also, if we are going to have company as a component of the regiment, I wouldn't mind seeing some specialized companies such as light/heavy categories for infantry, cavalry, and artillery as well functional ones like engineers and sappers but that would be a pipe dream.

In a way, it would be nice to have customized regiments, taking the page from unit template in EU4, perhaps similar to how unit type can be defined in Crusader Kings. A regiment designer or planner could have four modules for a regiment, each of which you were to select from the categories and the functions as described above. Could have two heavy infantry, one light infantry, and one engineer company for an infantry regiment. Engineer would be exclusive to infantry regiments, though not sure if it should be also available for artillery regiments but probably not. Once a customized regiment is created, it then could be constructed like all other regiments or even replace the vanilla regiment of its type.

You can create and delete regiment for each type but you cannot delete a regiment if it is the only remaining configuration for that type. It should permit for diversity of the regiments throughout the world to reflect their circumstances, particularly the terrain and the geography it was raised in or for. There may be a maximum cap on number of customized regiments you could configure, to preserve the gameplay balance if necessary. If you wanted to change the regiment composition, you can update or "refit" all regiments of your choice (not sure how that would work but can be simply for all regiments in a specific army stack) or all regiments in your entire national army for a cost and its drill as well morale would be reset.

Lastly and slightly bit off-topic here but related to the overall point of my post, taking a page from the flagship designer, I think it would be nice to ditch that designer in favor of an overall ship designer using modules similar to those used in flagship designer. Many modules would be exclusive to a specific ship type, while all others would be available for all. Each ship types (heavy, light, galley, and transport) were not truly uniform for all countries during a particular era, especially towards the end of EU4 timeframe. You have to consider materials, size, maneuverability, etc. Types of wood material is definitely not same in Asia as in Europe. In a way, ship designer need to be implemented to reflect the diverse circumstances.

There is possibly no way that Chinese or Indian warships resembled anything of the European design in 18th century, not that I am implying European designs were superior or inferior at that time. As for the flagship, I am not sure how much different a flagship could plausibly be from other ships of their type unless there are some specially built cabin or something? In any event, it would be kind of cool to have some customized ship for each type. I don't know if we should permit more than one custom configurations for each ship type, perhaps to force trade-off. Setting maximum cap to two per a ship type might be OK but I dunno. Again, I am sure this would be a pipe dream. *shrugs*

Simply put, I would like the army and navy to be more interesting than just plain 3 types and 4 types. That is all for my 2 cents here.

 

[Tweakee]

Proposal: Have the Mercenary Pool based on the manpower pools of friendly nations.

So when you want mercs, the recruit button is pulling from the actual manpower of nations in the game. If everyone hates you, no mercs will work for you. If war has drained the manpower of everyone, no mercs will be available.

If you're a nation planning to wage lengthy wars, it becomes much more valuable to maintain good relations with other nations to keep your merc pool as large as possible. You could also sabotage your enemy's relations to reduce their merc pool.

If you're a nation with a full manpower pool, you'll now be getting -paid- for whatever % of your pool you want to make available as mercs. So instead of full manpower being a waste of resources, it can become an opportunity to improve/recover your economy while providing mercs to your friends. To make it more likely that mercs are available, I'd have an "overflow" for manpower, so that say up to a year's worth of manpower over 100% is stored just for the merc pool.

It'd probably be necessary to increase overall manpower to balance the removal of magical merc spawning, but that's a pretty straightforward thing to balance - it's one number.

With this system, the game would no longer have mercs magically appearing. Nations with full manpower would gain a benefit from it. Lengthy wars would have a real, tangible gameplay impact. Diplomacy would be more important. Best of all, it's a pretty straightforward concept, and doesn't add a bunch of new numbers, modifiers or UI panels.

 

[CMDR_HERNE]

It would good if higher millitary tech levels significantly reduced or negated hiring of mercenries. To reflect standing armies of the later eras this game represents as we evolve our armies from the late middle ages to the early modern era
As an example In the 18 th century Hessian mercenarties or German auxilerries that were hired by Great Britain from Hesse? If you viewed them as hired then they are just a form of Condottieri, but that is behind a dlc paywall.

 

[AlknicTeos]

My first idea ingame is pretty everytime, quantity. I also care about my manpower. So I usually don't need mercs.
I also haven't read every post down here.
Anyway money was in war also short. Maybe some kind of slider for manpower vs eco. At begin in 1444 maybe only few manpower gain, 'cause the need to work in the economy. As you grow you may want more soldiers and can afford a maybe -30% production numbers for +30% soldiers ? Maybe also some kind of avaible slider or laws settings by tech for military service ?
And about mercs. make 20-25% of manpower gain to avaible mercs and with some attractivity in other countries. From the 20% manpower gain as mercs it gives avaible mercs for 1/4 of that country, 1/4 culture group, 1/4 religious group, 1/4 for near factions in war, before some weights. Maybe also some local extra mercs, if the province is poor in economics, but strong in manpower. Higher tolerance to those heathen or heretics could affect the merc numbers. With another limit, that in a holy war against another country stops mercs from those religions. Another weight could be, how much you want to spend for mercs.
From my knowledge there were the condotti in italy and the swiss mercs. First were rich countries, that could afford them, and the swiss then ? Anyway, later, when discipline becomes king, mercs lose some of their ability to do war. Maybe shorten the training time for regular armies by the time. A Longbowmen needs a lot of training, a swordsmen probably too. Holding a musket ? have the discipline to fire only and first, when the enemy is close enough and good teeth.
Also about my kind of idea for handling mercs would be, as described above, is, that the 1/4 merc pool redistribute over time. If there would be 100k in the habsburg, german, catholic, holy war against oe. And Habsburg drains their 100k, it would refill and redistribute it from the other german and catholic countries too. So, less mercs for other german and catholic countries and more for habsburg.

 

[ChloePech]

A thought; why not tie mercs to, instead of the geographic region bit thrown around (which would make France unlikely to hire German mercs which is odd) tie them to trade nodes? And perhaps have the quantity of trade power in a node determine how many mercs can be hired there and have countries with trade power there benefit from hired mercs? For example, this would mean that end nodes like Venice would have high merc counts (which is historically pretty accurate) and that hiring mercs would help the economy of those with power there; IE venice. Mercs essentially bring in money from foreign powers.

And restrict where you can buy mercs to where you have trade power and have hiring mercs from that region penalize your trade power there, so you're effectively paying trade power for mercs? That can help curb the "build massive stacks and ignore everything else" while making sure that merc amounts are variable and reflect the relationship of mercs to economies. It would also mean devastation would lower the merc pool