While the super realistic crash simulation is nice,the cars just seem to be plopped in this world without any real connection to the map.Now,It would be nice if when its snows or rains,the cars get wet or covered with snow,or when it hails the cars get tiny dents on them,also if you drive a lot on the map your car gets dirty.Also,functional windshield wipers and horns,and indicators that make a sound,as well as glass that can be broken in many different locations,just to tie the cars into the maps
This would be amazing, but as said earlier, it would be a lot of work, and it will probably never happen.
Likely to require a lot of computing power (even relative to what's already there), but I can't imagine the devs wouldn't like to do some of this at some point. Also, horns have already been added.