Imo the problem goes beyond the Faust issue.
The unit is simply OP. For 200 manpower you get both the vehicle and the crew.
That can be used in a number of way for:
Caping
attack any HMG not in garrison
Defend any point from a lone caping squad since one disembark and have 2 squad
moveable fast repair
a satchel transport
and on top of that a kamikaze mark target/barrage unit.
In addition the unit has more around x1.30 armor than Kubel.
I would suggest that the crew would become unable to disembark and that the armor is reduced even if mean increasing the HP.
The mark target and barrage should also be removed and usf as a whole faction.
Why u so hate it. Its cool commander but not really op as u think. No one use it in teamgames so i think this means commander its not op. Shermans are ok but nothing special, for late game jackson and scott are better combo. Wc51 dont save it and u if u want know barrage is bugged because if u kill truck after red flares barrage dont land and u lost 180 ammo and truck this happend to me almost three times so i give up with this commander. Imo the best part of this commander is mortar halftruck and cavalry rifleman.