The topic of this thread is Penal, lets move away from conscripts and maxim. This unit could easily receive minor buffs if when penal power level is decrease Soviet prove to be weak.
Another issue with Penal are the very strong offensive vet bonuses their receive combined with their very strong base stats.
They are heavily related as you will be facing penals or maxims. With the current performance of maxims you are seeing higher levels of T1 play.
We can not talk about nerfing penals without looking to buff T2 (namely the maxim) and/or T0 with the conscripts.
These units don't exist in a vacuum, they are part of a larger composition and you have to take that into account.