I don't know about the rest of those things but a 'hot pursuit' mode would be fun. Let's say when you're a cop you can drive any car with any skin, but it just put police lights on top of your car. Then you get to chase the 'bad' guy, or guys, and try spinning them out, ramming them into walls etc. When the bad guys car goes below a certain speed (maybe 5km/h or so) with a police car within a couple of metres of him he is 'arrested'. There are already people playing cops n robbers, this would make it so much cooler.