Let me preface this by saying that I’m very positive to almost all the changes in this patch, but since they are clear/outright improvements I don’t feel the need to debate them much.
However, there’s one change that I feel has a significant negative impact on the game. That change is the cannon backrow change where they retreat at zero morale.
Some starting points to work from:
Cannons now lose morale at the same rate as infantry, this means that the cannon backline typically will retreat around the same time as the infantry in front. This means that they suffer minimal (in my tests, literally zero for both sides) casualties.
Cannons are now (if they weren’t already) incredibly strong, engaging with only infantry and no artillery support is after certain tech levels simply throwing manpower and warscore away.
The conclusion to the above becomes that your fighting stacks should consist of equal numbers of infantry and artillery (since if they consist of more infantry, the last infantry regiments end up fighting without artillery, being essentially fodder/wasted manpower)
Onto the first issue:
Now, since your infantry receives the brunt of the casualties (due to the artillery being ready to retreat/already retreating once the infantry breaks), and you want to maintain the ‘magical’ 50/50 ratio, you’ll want infantry to reinforce your stack every time you consolidate an army. For any efficient warfare, especially offensively (due to slower reinforce speed), you likely want to consolidate after almost every fight. This means that you’ll want some pure infantry stacks ‘standing by’ (not engaging, as you risk them suffering heavy casualties for little gain) and after every consolidation reorganize your ‘fighting’ stacks to once again be 50/50 inf and artillery. This is a huge problem, having to reorganize every fighting stack to 50/50 after battle feels incredibly clunky/like a huge chore even in single player with pauses. In multiplayer I imagine it’ll be outright dreadful.
Second issue:
This issue is mainly relevant for multiplayer, but I think it’s fair to at least mention regardless. Since all your stacks anywhere near the frontline (your reinforcing infantry stacks can be quite far back, as they merely need to be present after the battle) are 50/50 inf and artillery that (with the forcelimit general change) likely has a general you no longer have any ‘vulnerable’ stacks. The most interesting part of multiplayer warfare is to in some try way force a bad fight for your opponents, typically this is accomplished by catching out stacks without artillery/general support and in ideal cases wiping them (forcing negative terrain modifiers) before reinforcements arrive.
This entire aspect of multiplayer warfare simply goes out of the window with this change, as there simply aren’t any vulnerable stacks to catch. The same can be said regarding reinforcements, timing them/slowing down reinforcements barely matters since the reinforcement stacks will fight at full strength on their own (cannon backline+general) not requiring the support of other stacks. Your actual decisions while controlling your units will hence be largely irrelevant/of very diminished impact.
Available solutions:
1. Making the backline artillery take less morale damage by a certain percentage, as has been suggested by Gnivom, alleviates both issues but doesn’t solve in particular the first issue (the second also persists to some extent). You will still be (assuming that you want to win your battles) greatly incentivized to reorganize your entire army after every consolidation, just to a different inf to cannon ratio.
2. Another solution would be to simply have artillery take casualties when they take morale damage. This would solve the first issue, but the second would remain. It’d also change artillery cost and performance by a huge amount, opening up other potential issues.
3. Simply don’t make cannons retreat when their morale hits zero. This is how it works on live, and I struggle to see the disadvantages. The main reason for the proposed change seems to be that it’s ‘wrong’ to get the full benefit of these strong cannons while simply employing one stack per battle. I personally find this argument to be quite weak as running cannon stacks in battle is just mandatory in either scenario, and this fact doesn’t change because you have more of them. It should also be noted that the cannons regardless don’t perform in a vacuum, you still need infantry to support them to bring out their power, meaning that the ‘alone’ cannon stack isn’t just functioning on its own, it requires support.
Possible advantages of the beta artillery change:
As mentioned above I’ve struggled to find the advantages of this change, but here are the ones I can find. Not having the possibility of vulnerable stacks being ‘caught out’ is a potential advantage from beginner to mp perspectives, but any beginner-friendliness accomplished by this is to me greatly outweighed by the clunkiness/complexity having to reorganize your stacks after every battle. I also think the economic impact (bigger % of artillery means bigger army costs) can be positive, since ducats can be a bit too readily available in the later stages of the game. However, this result could just as easily be accomplished by simply increasing the maintenance scaling with tech slightly, so it doesn’t really justify the artillery change if it doesn’t bring other additional benefits. My conclusion is that these pros don't come close to outweighing the negative aspects.