As was stated previously, how do you want to fix it with little work?
Right now, 1v1 and 4v4 balance are opposing sides of the spectrum. Balancing for 1v1 makes 4v4 horrible and vice versa.
You would need to rework the maps as the map layout in 1v1 does not scale to 4v4, they are usually far more narrow and long. Less frontline works great for Axis due to PaK, MG42, MG34, Jagdtiger, Tiger, ... The longer map means it's harder to pressure with the strong USF infantry early/midgame. If you are forced off you yield for far longer than 1v1.
Resource income is another issue as do some abilities.
Yet the problem is, these scaling and map problems would need major manpower to fix. I do not think that Relic is capable of doing this.
