Read through your post, we think the next update will largely resolve many of your concerns. We don't think veterancy on the whole is an issue, perhaps on one or two units. The Panther at veteran level 2 might be too strong for example, this is something we're keeping our eye on. That said, Soviet mid-late game will be on par with the Germans in the next update. For example, IS-2 and ISU-152 will take on a more significant anti-vehicle role.
Relic will buff the soviets late game hughly it seems.