What if you could create a system where the drivetrain or the interior react to the damage sustained outside (ex: In a huge roll down a cliff, interior trim falls off and flies around. In the drivetrain, the engine dies and gets disconnected, falls out, and tumbles down the cliff.) It would add more realism.
Does that not happen already? I thought it would... I do know that you can break drive axles, though I hope the engine can fly out aswell.
I think they are working on it, and I'm pretty sure the trim (on some cars) falls off, I don't think it would be too Fps intensive as its just parts disconnecting