i really like someone's idea of upgrades within t3/t4 structure.
i think it went like:
basic t3/t4 structures are cheap but they have to be upgraded to get t34/su85s out.
i think this would make sov mid game vehicles like t70, su76, or even quad m5 out earlier for more interesting mid game for sov.
i really like it for if i wanted su76 to support for t34, i can do it cheaply but if want to utilize t34 +su85, probably one the most effective combo, you need to invest more etc etc.
Yes, that worked for the Panzer Elite back in CoH1, I'm pretty sure it would for the Soviets. Keep the cost for a fully unlocked tier 120 fuel, but make it 60 to build a tier and 60 to unlock its big unit, and buff the T-34 and SU-85 accordingly. The long-discussed swap between T-70 and SU-76 could also work, the latter needs a buff however.
I have a feeling that Soviet's T1 and T2 are fine, minus the overpowered snipers that need a nerf while conscripts/penals could use a little love. The problem is that their T3 and T4 just aren't competitive, which leads into call-ins being widely favored because not only are they cheaper, they are also more effective.
As VonIvan said, Soviets are a powerful faction... if you cheese and stick to a couple of tried and true builds. Try to use anything other than cookie cutter units, and unless you outplay your opponent, you will see why those units aren't cookie cutter. This sucks and needs to change.