A very nice feature already implemented is - in my opinion - that the view is toggled out within cars. That gives the driver the 'overwatch status' he needs, to maneuver his car in most of all situations correctly. Also it increases the immersion, because you don't just look through the windshield, but you also get a feeling for the car you are steering as driver.

Nonetheless in some situations the out toggled view is not enough to control adequately. Especially if you drive in moderate or even heavy curves, or if you turn right within a city, in reality you would face the direction you are moving to. That provides you your 'overwatch status' in such tricky situations.

In Arma the orientation of the drivers head is always facing the front. Yes, you can turn the drivers head by using several methods. For example
1.) Num-Pad keys
2.) Freelook mode and mouse
3.) Track IR
The best (the simplest) way of these three is the third. But you have to buy and install Track IR hardware.
The problem with the other two is, that you use for example
1.) your left hand for moving forward (your hand is in typical WASD-position)
2.) your right hand for steering right (your hand is on mouse)
3.) and now you would need a third hand using the Num-Pad keys or using a second mouse for changing your views orientation.

Of course you can control your car by WASD keys only and use the mouse for orientate your head. Indeed I use this method, when I steer a car in 3rd person. But the new system of car control expects you to use your mouse for turning and Q, W, E and S for acceleration. So I would be a very nice feature, if the heads orientation is influenced by - let's say - the wheels orientation automatically. That would solve our problem to need a third hand - and like the title says, that could be implemented in helicopters (and maybe other vehicles), too.