....
I don't know if its stronger, but mp40s have significantly better dps at point blank. Given that they have really good camo, I'd rather take that and get behind the squad I want to use tactical assault on with mp40s than do it frontally with stgs (I'm taking a bit of a leap since the only reason tactical assault would be better with stgs is if you used it in a traditional infantry engagement). It's all about ambush and cutting off retreat paths now, and I'd rather have massive dps at close range for that.
Tactical movement should be used in frontal fights only under specific circumstance(especially for ST since the drop of DPS due to entity loss is very high) due to the penalties.
The ST ST44 could also flank enemy units and use tactical movement the same way, only they would have higher DPS at longer range and could get wipes on retreating infatry at longer ranges.
The main issue was the 100 mu investment for the ST44.