I think the biggest problem is the fact that late game Super Tank wise OKW has the advantage. Even if you get 4 t-34/85s and your teammate gets like 2 IS-2s vs a KT and JadgTiger supported by either paks or shrek'd volks you're gonna have a rough time. And considering a lot of allied players like to blob like axis players in big team modes having the stuka out really helps as well. There are other issues like dbl Kubel spam allowing the axis players to cover a certain amount of territory until the 5-6 min mark during a 4v4 is huge in giving them a resource adv as well. Here's a good example of this:
Vs A Relic Dev too
When balancing these super tanks/arty/kubels we need to keep in mind not to render them completely ineffective, but adjust the way they operate as killing machines so that people actually have a chance in-game when facing them.