A lot of people fail to make use of it's very good arc and sight by using it like a ZiS gun in CQC. But yeah ultimately the biggest downfall of it is it's 4 man squad. Would be nice to see all USF weapon teams get bumped up to 5 men no?
I would like to see USF support weapons get bumped up to 5 men. Not that I think USF need a buff overal (they don't), but at the moment there is very little reason to make HMGs and AT guns because they just die so easely. This is especially the case against Ostheer, as their sniper has a high rate of fire, their mortars fire rapidly, and Rifle grenades clear them out from long range (with maybe 1 burst from their LMG to finish the last guy off). An extra guy in the squad would certainly help a bit to make the support weapons a more attractive option over just plain rifle spam.
You forgotten something? Maybe something like PaK40? It is still one shoot wiped by Shermans HE rounds.
Honestly I don't fear shermans that much when I play ostheer. By the time they have a sherman, my PAK40 is likely vet 1 from shooting at the always-present M20 or AAHT. Vet 1 gives me TWP which makes it extremely good at dealing with shermans. If you have a panzerfaust nearby you are likely to kill it, if you have a second PAK40 already (say, if you are going mech assault and don't need early T3 tech), it's an almost garuanteed kill. Now M8s on the other hand... Those are nasty.
In any case, the sherman ammo switch ability is a rather poor design choice in my opinion. It needs to have big splash because of the big penalty of not being able to damage enemy tanks, but big splash leeds to 1-hit wipes. Poor design. It's alright on the ISU152 because that thing can't just pop up everywhere but it is bad for the sherman.
Having said that, two wrongs do not make a right; USF having weak-sauce support weapons just because the sherman has HE shells leads to linear and spammy strategies.