There is plenty wrong with the JA/China balance. China seems to be raising 2-300 divs which from a manpower view is perfectly reasonable but preposterous for being able to equip and supply them, especially in view of the legendary levels of corruption. In addition NAT seems to be able to quite happily upgrade them all from 36 to 39 pattern and beyond, and all on an base of 40 or so IC. If I could do this for Germany I'd be someone to watch out for...
While JA historically couldn't take china, by the same token the natchi army was almost totally ineffective in attack and this is not what happens in the game when it has 300 divs to play with. The current level of NAT strength looks a lot like another nerf that should have done differently. What really prevented the Japanese from doing more was lack of supply and inability to pacify the countryside. There was never any realistic possibility of more than localised attacks from the NATs.
I suggest the following:
--a new level of supply 'Defense supply' where attack factors are halved but defence factors are as at present. This would replace the current default of attack and defence factors at 100%. It would promote stalemate where resources are scarce--e.g. JA vs NAT, without requiring a big strength nerf, and is reasonable in that many sectors in many theatres were 'quiet' a lot of the time.
--Change 'Offensive Supply' to be attack and defence at 100% which is currently standard supply. Maybe let arm/mot/mech units have 100/100 all the time and perhaps 110 or 120% attack value for offensive--they were dangerous at all times and places, and the war ebbed and flowed around them. This is one way to do Barbarossa shock effect, for example. By the same token, these high-tech units are (or should be) few in number and their relative value is not high enough at present.
--make it more difficult to achieve 'Offensive Supply' e.g. require an HQ within one province as per the current command bonus. Furthermore require the HQ to wait before reissuing Offensive supply so they can't be shuttled around the front firing off groups of attackers, or possibly make the HQ immobile while Offensive is in force. This would actually model nicely that offensives tended to run out of steam as the attackers got further and further away from their dumps. Also realistic--very hard for thousands of tons of food and ammo to walk around!
--make HQs cost drop more as techs improve, so this flexibility is more available to advanced nations than underdeveloped ones. As it should be.
--make ESE effects larger with distance from supply for Offensive but not for Defensive supply
--make HQ supplies capturable should the tables be turned e.g. DAK at Tobruk in 42
--The Offensive Supplies belong to the HQ, not the ground units. So the units trace ESE to the HQ--which is in effect a nice additional bonus to start with, which steadily reduces--while the HQ traces its own supply line back to the capital. This should work in such a way that an HQ will steadily deplete offensive supplies if it's far away from home and not backed by a 1944 USA-style logistics tail.
--Allow the player to control how many days offensive supply are stockpiled up to a maximum which could be determined by a tech, and rather than this being 'instant' it should take a while for these supplies to accumulate. This in turn should be a discoverable intelligence item, as indeed it was historically.
--Allow supply dumps to be bombed and thus reduced once found
--Allow the HQ to be moved but only at the cost of abandoning the supplies. For instance, if you're USA, you may not even care...
--do not let nations at peace stockpile supplies in an HQ, which gives aggressors a large initial advantage--as it should be.
--Need AMPH HQs which prepare units about to load onto ships.
Now I'm thinking as I go along here, but this last proposition raises some very interesting possiblities to fix the amphibious side of the game.
For instance:
--you can always load a single division onto a single transport and make an uncontested landing in Defence supply (You still have 50% attack after all). This happened, and often, and much of the Japanese operations in 41 and 42 were just like this, as was the German invasion of Norway. Though perhaps part of their preparation event could be a 'free' AMPH HQ...see next point.
--AMPH HQs should have a range and a capacity in divisions that they can bring to attack supply and combine into a single force, and these should increase by both technology and experience. This allows you to put a division, corps, army or army group on the beach in a single stack in attack supply, and control the distance in provinces (1,2,3) that they can be sent--not halfway around the world in one move as at present. Standard command penalty on trying to swamp a defender with multiple individual units and no AMPH HQ--this sort of this went wrong all the time, e.g JA at Guadalcanal. Would also make taking staging bases and island-hopping work more like it should. In addition, I don't think anyone sent invasions much beyond the range of fighter cover and this too needs to be worked in somewhere.
For instance, we could give GE a level 1 (one division) AMPH HQ in the Weserubung buildup, which lets them maybe take Oslo without too much fuss if there is air and naval support. For the rest, well, perhaps they'll have to invest in paras after all to support the other attacks! This also gives them one to play with for Crete, which is historically accurate enough and does not need GE to commit to an entire AMPH tech tree, unless the player wishes to for other reasons.
At any rate, the more Amph attacks you make, the better you get at it and the more ambitious your next one can be. But you can still progress, perhaps at a slower rate, learning as you go...
Note also that the largest invasion force ever contemplated by the USA for Operation Olympic was around six divisions in the first wave, so this should tell you how hard it really was.
If you don't have good AMPH HQ tech one way or another, though, it should be VERY VERY hard to pull off a successful landing against serious opposition. All the historical commanders knew this from the start, yet the game fires off invasions with carefree abandon. Eisenhower knew that if D-Day failed, the repercussions would be so large that Allies may even have had to sue for peace. So they didn't proceed until they were as certain as they could be that it would work. Much to the disgust of Stalin, but that's another story...nevertheless, the loss of even the five divisions at Normandy would have been a stunning propaganda victory for the Axis, however little it actually impaired the Allied war machine, and the possibility was unthinkable.
I am in favour of a big dissent nerf for failed amphibious invasions by democracies, more for realism than anything else, and to encourage the player and AIs to treat them with due respect.
So, looking again at JA vs NAT, you should be able to lunge forward JA a province or two, then poof! your supplies are used up, you have to pile some more up which takes more months. In the meantime you don't particularly have to worry about being steamrolled by 300 divisions because they don't have any supplies either--but you'd still have to maintain enough force on the ground to contain them. And so on. If you intend to attack NETH/UK/USA, your supplies go there intead.
The point here is that the player will have to plan ahead and decide priorities, and then there is a level of commitment to these decisions that isn't there at the moment.
--most Chinese divisions should be no better than Mil1 and stay that way. A handful were equipped and maintained on something resembling a modern scale. Where Japan seriously tried to move them along--pre-1941 and in 1944--they didn't have much trouble doing so supplies permitting.
I have been ranting (I admit it!) about the failure of AOD to adequately capture the flavour of WW2 warfare in other threads, and logistics is one more example. AOD could be a great game, it's still not bad but...