I actually have few suggestions all about vehicles

1. Suspension simulation
2. Being able to puncture tires + a new gadget: road spikes
3. If helicopter gets shot in the tail, it falls off making it very hard to control the helicopter
4. If helicopter gets shot in the main rotor, it breaks and the helicopter simply falls
5. New vechicle, something like transport helicopter but for land, it could fit up to 8 people including the driver