This was suggesting in the heat combat thread. Regardless of the future of heat combat in general, I'm willing to include it in the upcoming test.
Considering it's a vehicle parameter that allows turning on the spot and doesn't have anything to do with moving the turret I really couldn't see why both would be disabled.
Patches ago you could smack people with your turret and do cool vehicle tricks. And you can also reposition to allow someone in your hatch to throw stickies/fire mortars/fire rpgs/shoot people from it if rotated correctly.
#1 was an exploit, #2 results in missed shots and blown up faces way too often for my tastes I will admit that it is a thing to do, though.
I find it reliable to be able to sticky stun from the 2nd hatch on an APC. It does take some coordination with 2 people however.
Stickies work quite well since you toss them from a higher point on your body than the mortar and you have to compensate a lot for their weight and thus you aim way higher to land a hit.