Or reduce the dmg on the gun of the m3 and make sure if it gets hit by faust the squad inside loses half its number(which is realistic if a thin skinned truck gets hits by a rocket grenade)...that way they can't charge with flamers with impunity knowing they can get away even with getting fausted and then pop out of the vehicle.
Actually very interesting solution. Make Faust kill squad models inside M3.
Concerning M3 I think it just needs to take more dmg from small arms fire, especially when up close.
When I play axis I too often see soviet player go really aggressive with flamethrower engi or penal in M3 up close with grenadier squads on low hp or 3< models left.
Too often the gren squad will die or drop to 1 model on low hp from the flamethrower before you can get off a pz faust.
If the pz faust goes off the slowed M3 will still be able to kill the forced into retreat gren model left.
Combining that with mines I too often see myself losing full gren squads early game and to be honest I think this is the biggest problem. Axis is all about preserving those precious gren squads and losing 1 or 2 squads early game really handicaps the ostheer faction.
Thus I think the M3's mobility or dmg taken at close range should be fine tuned. I don't have a problem with the M3, I just have a problem with the way it enables Guards with LMG or flamethrower squads to squad wipe ostheer squads.