The KV-1 is a very good call-in.
Overall, I'm not a fan of the double T-34/85 call in (even though mark target helps) The wait is much too long. The single T-34/85 from advanced warfare is better. But both call-ins are expensive and come late. Ditto for the Sherman, except I really don't like its HP.
I still think that early T-34/76s + quick call-ins for precipitous attacks are the key. The T-34/76 is the baseline armor. Then buff the tank force with the KV-1, Sherman, or T-34/85.
Is-2 is too expensive for its ability (its in the same price class as the tiger but is much worse) and the KV-8 is situational.
For soviets, I don't think T4 and IS-2 is worth it in many cases.
For Germans, T4 is not worth it but the Tiger tank is.
I can only partially agree with you. KV-1 is a really great call in tank. IMO it performs the best in conjunction with SU-85.
Usually I build my fleet at 4 tanks total depending on what the opponent is throwing on the field.
If I see lots of infantry I would go for double KV-1 and double SU-85, if there are lots of vehicles I will build 3 SU-85 and 1 KV-1.
Same with supporting units. Infantry - double shock troops. Tanks - double ZiS.
My point is that if you combine survivability of KV-1 and AT killing power of SU-85, you should have a solid combined force army.
Throw in B-4 for more damage, and you will be more than fine.
I've been doing pretty good with this commander in 2vs2 and up.