I've tested the firing from vehicles feature, and I have to say it is great, but there's one thing missing.
The ability to fire from inside the vehicle. Of course, heavily armoured vehicles should be left alone, even the MRAPs, but the vehicles I think should be tweaked to allow this feature are the civilian ones.
If you sit inside an SUV, Hatchback or the cab of an Offroad, you can see that you have your primary weapon between your legs, ready to use. Only you choose not to, and I was hoping this would be changed.
Granted, you'd have to shoot through the glass of the vehicle which no doubt would break eventually.