I agree with most of the post, but I have to point out that this the way of thinking that lead to power creep.
People complaint that conscript do not scale well compared to Penal so conscripts got buffed and now people its the other way round...
One should simply redesign things with:
either
create different play styles with Penal as cheap SMG cannon fodder units and conscripts as defensive infatry
or
Replace Penal with cheap AT infatry in T1 and make Penal a doctrinal unit available to NKVD armies so that there 3 types of armies, Guards/shocks/NKVD.
They cost more than conscripts, they require a specific tech. AND on top of that then require and additional upgrade to even get close to competeing with the worst mainline in the game (volks), and then to make matters even worse, its the slowest opening in the game.
its perfectably acceptable for a unit with that high of an entry barrier to scale well.