Comet should get its rear amor nerfed to 100, in fact only KV series should keep their rear protection (which is an out-dated design)
BTW, have you ever consider giving soviet a REAL tier4 tank aka make T-34/85 a stock unit while make a scaled downed t-34/76 back to tier 3? Soviet T4 is quite expensive(and even more expensive with cons' side upgrades) , T-34/76 is outmachted when it's came out, and flanking is equally if not more suicidal since panzerfaust available to volks now
With a buffed SU-85 and T-34/76 buffs I think it would be enough. Sure the T-34 is not the greatest tank, but it means you can field a cheaper tank screen which does decently at warding off infantry and vehicles while also being a risk to other mediums up close or via flanking. SU-85 meanwhile deals with the heaviest of tanks so as long as it can be screened. More tank combined arms that way.