I kind of agree. While the OKW and Soviets have their issues, having actual line infantry and not pseudo elite as their basic troops adds to the strategy needed for both factions.
On topic, I think the reason people want Grenadieresque Conscripts is the lack of capable, cheap frontline troops in the Red Army. The jump from poorly trained farmer with rifle to elite Shock Troop and Guard is quite high, and Penals make little sense as a nondoc unit. I know that when I think of the Red Army in WWII, its core is capably equipped troops that compensate for their poor training with both numbers and experience.
Honestly if most Conscript heavy but crappy Doctrines (I can't think of any by name, but I'm talking bottom of the barrel commanders here) had Frontoviki upgrades that turned Conscripts into crappy Riflemen for a fur cost, I would be happy. Usage would be like Troop Training.
FRONTOVIKI UPGRADE
35 fuel
Decreases received acc per model, increases price. Units gain Frag grenade as ability. No more sandbags.
Two upgrades available for 45 munis, DP28 or SVT-40 package.
The name you chose is ridiculously good, but the whole problem with conscripts is they should scale as stock units, not with more doctrinal bullshit. I believe most considers buffed PPSH upgrade as a good idea, iconic, not LMG cancer etc. Now we take your Frontoviki Upgrade, replace packages with PPSH's and add sandbags back (why?). As a stock upgrade, it should be moderately expensive and well-timed, so placing it in T4 seems good. Cost to be aligned.
Alright, enough of talking obvious.
I also had an idea of making penals the true stock soviet elite infantry (lol) so they could start with cons and as the game progresses switch to penals for 40 fuel late game or have a well scaling inf from the start. Shame this idea makes no sense at all