I think it would be nice to be able to switch from he to ap and ap to he without firing with like a short unloading period and the the full reload of new shell. Sometimes you dont want to give away your postion especially when your changing to ap to deal with a tank.
Another change that would be nice is for example if both my loader and gunner have faster loading and my loader dies there should be a way to choose my gunner to be the new loader so I dont lose the faster loading perk this would also help with driving perks and gunner perks.
Small thing but unless its been changed already being able to see what type of ap shell a tank has in its hanger overveiw would be nice.