I dunno, StuGs are pretty obviously superior to SU-76s aside from the latter's free barrage (which is more of a small bonus than a significant facet, unlike say AP shells with the Sherman's HE). The proposition sounds a lot like when JPIV were in OKW T1 to me, except in this case they're way cheaper individually instead of having good vet 5. I'd say we're better off messing with 222's stats.
I'm totally cool with putting Werfer in T3 though.
Is tiger locked behind T3 or T4 upgrade or just the CP wall?
If I could get stugs out T2 and no lock behind tech advance on call ins then it will just be another Soviet T2 wall into call ins.
That's a pretty fair thing to fear. If a faction were to only have StuGs for vehicle-based AT, I'd think I could manage with it.