The thing is, cons underperform quite severly lategame, and have lost most of their utility with nerfs to merge, sandbags, and molotovs.
Cons lategame can be buffed quite easily without affecting early game performance by giving them a nondoc weapon upgrade at T4 (SMG), a global buff upgrade at T4 (ie. less cost), or better veterancy unlocks (ie. more accuracy at vet3).
Cons don't even need a direct buff. Making penals have a unique and scaling role (instead of being cons with better AI and no AT) would give Soviets viable lategame infantry while not changing conscripts at all, making con heavy builds strong early game but weaker as the match progresses.
Or this...make PPsh nondoctrinal....or Penal Batalions useful