I my view, tanks, artillery, and infantry units don’t just represent those things, but rather their units. Most tank, artillery, and infantry units during World War 2 contained some organic AA guns. While there are obviously differences in the size of divisions between the powers (Soviet divisions and corps were smaller than Western ones, one reason they were able to rack up such large numbers), I think a unit represents X number of soldiers, tanks, AA guns, etc. (while actual AA gun units are for dedicated anti-aircraft units which exist semi-independently of other divisions).
I’ve heard suggestions of giving artillery anti-tank capabilities, similar to anti-aircraft artillery in Global 1940 (North Africa’s anti-tank gun piece has something similar too). I think different win rates between different units is mostly represented well (as I hope I’ve somewhat demonstrated above).
