Big difference between purely close range orientated Stormtrooper MP 40s and the all-ranges orientated Falls FG 42s though. Assault and Hold also doesn't let Stormtroopers sprint in for maximum damage / minimum exposure.
Maybe an adjustment to their DPS can fix it.
IMO usin them with valiant assault may lead to severe consequences due to :
* Their RA not being changed thus still dropping like flies and bleeding big chunks of manpower.
* They cost big popcap thus preventing huge armies or blobs considering OKW's already high popcaps.
Thats why I think making them a infiltration unit with :
1) A slight adjustment to their DPS
2) Removal of the bundlegrenade for fuersturm Model 24 or Democharge
3) Removal of PFaust
That way they will not be viable as mainline infantry since they will not get snares or super effective nades.
They are also not popping out of buildings and infiltrate via paradrop. Making an infiltration unit like that can be very unique for both Fallschrimjager and OKW.
( Yes I really like Falls and pressing that hard for that reason so excuse me if I'm being a retard
)