IMO the problem lies in the team weapons.
German team weapons are at a disadvantage because a) they have equal armor to the soviet counterparts and b) because all support weapons have the +25% increased received accuracy modifier.
Now, soviet crews have 6 models and german crews have only 4. The weapon is lost if only 1 guy is left. When you put a + b together it's quite clear which one dies faster. However, german team weapons don't bunch up as bad as the soviets do, for whatever reason.
The same fact somewhat applies to the grens vs cons but grens vs cons match-up is quite balanced because cons win up close and grens win at longer ranges.
