What we need are things that would sell in quantity, the T-34-76 is the best example of this. I would have expected that a T-34-85 would be next except for the existence of the plastic Warlord kit which reduces the potential market for them.
What I would like to see includes:
SU-122
SU-100
And I suppose the SU-85 to go with the T-34-85s.
All three are superficially very similar vehicles so I wonder if a single kit could accommodate all of them, aside from the different guns and mounts the arrangements on the casemate are different and there is the cupola on some.
T-70
SU-76
After that we are in the land of the heavies, KVs, ISs, ISUs and so on. No one needs a lot of KV-2s but it looks like it is only a different turret from the KV-1.
There are interesting pre and early war things as well such as the T-26 but are Spain and the Winter War sufficiently popular?
I have to admit whatever the Russian surprise is I am probably going to buy it.