Great idea. I think this is one of the main reasons most people don't want a gunner for their GV. Then all they can do is drive.
In AA vehicles, driving is plenty easy from the gunner position by using rudder.
In Tanks, most shots are made while not driving. By allowing the driver to take the pintle position, enemy GVs could be spotted easier + the guy in the pintle could tell the main gunner which way the gun is pointing.
On another subject, when do we get the turret position indicator? It's a real pain sometimes to get the gun where you want it because you don't know which way it is pointing.