A 5x MP40 upgrade would be a great addition to the OKW arsenal imo.
It would provide a decision between keeping a decent long/medium-range combat effectiveness for holding the line, or give you some firepower to assault a position. Reminds me of what Relic was thinking of when they thought up the Hammer and Anvil upgrades for the Brits.
Agreed 5x mp40s for volks would be a great addition to turn them into a assault/flanking squad. Mp40s would have to be buffed a bit though coz they suck atm.
Volks with mp40s worked great on vcoh and provided nice synergy with rifle volks and other long range units, I don't see why it wouldn't work in coh2.
When they upgrade they could get the old potato masher back but as a downgrade would lose the panzerfaust.