Right now vehicle physics in Arma 3 does not differ much from Arma 2 and Arma and that's an issue.
- Suspension must be simulated properly (to deal with all bumps and other stuff on the road);
Single rock lying on the ground can leave the car without wheel(s), when in reality suspension would deal with it.
- Vehicle collision are very strange at the moment. You can't really ram any other car if it blocks your way. Even if you are driving M-ATV and the road is blocked by Toyota-Prius-like thing it will still make you either stop or flip or fly. And this is only ramming let alone pit maneuvers.
It would be nice to see some improved vehicle physics that would not be buggy and obsolete in 2014. Arma 3 already have a planned DLC that improves helicopters physics, so why not improve the vehicle physics as well?
More particular examples of "what's wrong with vehicle physics in A3?" in video (Dunk, thank you for filming that video):