Really bad idea IMO. That would make MG's significantly worse. The essence of CoH has always been the ability of certain types of unit to counter multiple types of another unit. Making one unit immune to another's ability is lazy and poor for dynamic play
Penals are good as they are now. I use them often at a high level (top 50 with each faction - Ozena) in both 1v1 and 2v2.
Conscripts are the core unit of Soviets. Stop trying to make Penal Squads the CORE of the soviet army. Also, just because you play 1 or 2 games with "TRYING PENALS OUT" doesn't make them bad.
Soviet players can get penal squads at the same time and for the same cost as soviet snipers. Whenever you get snipers, HEY you can buy a penal squad. Think as penals as a More defensive/more hp sniper squad and they A.) counter grens and B.) counter bunkers/heavy building play.
Also, the metagame for ost. is x5 Gren squads into LMGs (or what ever the hell they want), therefore, Penals DO beat grens (un-upgraded) and beat them when penals have Flamethrowers.
I've been trying a x3 con-Molotov-T1-x1-2 penals, start, when my opp. starts as x5 grens and its been effective(there is a window where you can get pushed off so it's difficult but, when the 1st penal comes out, you get to push back).
If I have time tonight and my enemy goes x5 grens start, I'll try my afroementionedd BO and I'll save the replay (regardless if my enemy is awful or not, hee hee. However, that doesn't mean: SEE I BEAT THIS GUY WITH PENALS, PENALS ARE GOOD, that's my not point of the post/replay. My point is to show penals aren't "god awful/cannot win game"). Are penals a little expensive, maybe. are their reinforcement costs too high? yes. Are they useful in EVERY GAME? no.
For immune to "PINNED" (should be the title), I completely disagree. I do not want to have nightmares of DAWN OF WAR2- NO PINNING HMG games. Penals in small arms fire dominate MG42s, your conscripts should be the ones 'absorbing MG42 fire" and/or flanking with molotovs anyway.
If anything, MG42s need a slight buff.