A player on the soviet side (a player with a full acces and a premium account) has acces to 2 vehicle squads - T-34 (medium tank) and KV-1 (heavy tank).
While the same player on the axis side has acces only to Panzer III (light tank) and Panzer IV or StuG III (medium tanks).
So - if a player is using two tanks instead of the tank + a plane, the Soviet side is clearly a better option for him.
My suggestion is to assign Panzer IV F2 to the 18th Panzer Regiment (first tank squad), while keep Panzer IV G and StuG III in 201st Panzer Regiment (second tank squad).
I think that this will improve game balance.