They would be a bit better if there would be an option to buy PTRS/DP-28 for ammo. So you could call them in and choose to have anti vehicle or long range lmg unit, like in Theatre of War:
Other imbalance - Panzershrecks seem effective at infantry, they can hit inf models and kill them with 1 hit, yesterday I killed a soviet snajper unit with 1 shreck hit from close distance; but PTRS seem ineffective against inf.