This is my personal opinion and you do not have to agree with it:
Soviet faction design (imo) was to have average stock units and very cost efficient call in units.
5 stock units come out better from the patch (+1 doctrinal), that imo is redesign because SU depend allot less in doctrinal units to fill the Gaps.
Sov reliance on doctrinal units wouldn't be bad if they had access to a greater number of viable doctrines, or if doctrines had more variety within them. However the reality is that nearly 3 years on there are at most 3-4 viable doctrines for sovs, and with the linear CP system there is little variety in how to employ those doctrines.
In a game like CoH where resources are so scarce and map control so important, if a unit is not cost-effective then building it can cost you the game. If a unit is hardly ever worth building, what's the point of it even being in the game at all?
To use the t34/76 and SU85 as an example: prior to the preview the t34/76 was hardly built because it had poor stats and was rarely worth the micro needed to keep it alive. The SU85, while great against mediums, struggled against heavies bouncing shots at its optimal engagement range. In team games (where armour play is everything) this forced the soviet player to either spam SU-76 or use one of a handful of doctrines with t34/85 or IS2. Trying to make use of t34/76 or other 'non-meta' strategies would be punished hard and usually result in a loss. This reduces enjoyment and replayability for players of both sides because most games play out the same.
Now that t34/76 and SU85 are actually worth building, the SU player has more than one option on how to play. It's not like seeing these units on the field is suddenly game-breaking, they still have plenty of counters. It's not going to radically change the faction, it's just opening up more valid ways to play it.Yes, there may be some unforeseen balance consequences but that is why we have the community testing the changes before they go live.