Soviets have the best tanks in the game, so their teching is fine imo. Once you actually access the T-34, it's unbelievably cheap relative to comparable tanks.
Light tankovy could perhaps be lowered but I still think heavy is fine where it is. Paciat check your messages.
The Tank Hunters are fine, just use them like the description says: in groups. I usually use 4 of them: they beat every vehicle the PE or WM can throw at me. They are even better in a trench.