Next up was Obersoldaten. In an equal 4v4 fight, the Obersoldaten won almost every time. However, Obersoldaten require a vulnerable base structure that costs 120 fuel and 200 MP where the Penals need only a cheap structure that costs 160 MP and 10 fuel.
Putting up your tier stucture up close to frontline is not a problem of Obers nor Penals. SU player puts it in his base sector.
Let's me put it this way - isn't SU T1 is more vulnerable than OKW T4?
Additionally, the Obers themselves cost 400 MP, to the Penals' 300 MP. Thus, you can get 4 Penal squads for the cost of 3 Ober squads, and in that situation the Penals won every time.
Penal start is very slow. You should use that to your advantage and take superior map presence and field luchs fast.
Just think about it this way - how many combat squads OKW will have by the time when, say, second Penal comes out, given that SU player went T1->Penal->Penal? Something like CE + Penal + Penal against SP + Volk/Kubel + Volk + Volk.
Which side will have map advantage? Who will field light tank faster in that situation? What can Soviet T1 start to do against light tank, except trading AI for AT by upg. PTRS?
The most obvious counter, MGs... Well, you only need one Penal squad to flank, and suddenly you've lost your MG (and any nearby squads) to a 45-muni satchel. The satchel has a 4 second fuse, and it takes 3.5 seconds to pack up an MG-42 or MG-34. Eek. Not to mention that the MG-34 is a pile of fertiliser and leaves the OKW without a real MG.
Again, you let your MG to flank, which probably means that you've left your 260 (or 210) unit alone (provided no scouting/screening) against, as you say in your scenario - 600 MP army.
IMO the examples you provide either out of real combat situation as well as your "Penal Problem" is not a balance, but a skill issue. Your personal skill issue.
Obers being not good (mostly timing problem) are not Penal issue. Crap MG-34 neither.
Come on, dude. Failed to dodge satchel with your MG then came to forums? How about to pack up and run 2 secs earlier if you found yourself in such situation?