I have been playing some Total War and I have a couple of ideas for future update:

1. China is too weak - In every game, Japan punks them and takes them out by the end of 1938. This can be problem in base game a well. One item that would be historical and give China a chance would be a logistics modifier that hurts Japan's logistics as they go into mainland China. Just like Germany, Japan got bogged down more due to logistics than China's military prowess.

2. USA is too powerful - I am playing USA as a human and I can mobilize and get rolling by 1938. I think there needs to be more great depression type focuses that weaken my production (especially navy). This is kind of an issue in base game but the base game also short changes USA on factories. I feel like the factories used in Total War for USA is accurate, I just think USA should have more limited access to these factories until later in the game

3. Ethiopia encirclements - In several instances, as UK, I encircled Italians in Ethopia and got them down to one land without a capital city and they were not facing any supply issues. In fact, due to sheer numbers, they broke out. (Granted some of this was on me as I was using weak colonial garrison units to hold them in). However, I was surprised by the fact they were not facing attrition with encirclement. Not sure if this was a bug or not. I experienced some similar situations in North Africa but not near as bad. Also once you take all of the ports, it did start giving them attrition (even the encircled units). I have only caught this happening in North Africa. Other areas tend to play the rule correctly.