I want something nasty and dangerous !
Some japanese Touge style tracks, and some crazy mountain roads.
Something like Pikes Peak, where we can run the nasty cars!! Even pikes peak reversed would kick ass!
It's hard to say what would be a really good addition though,
there are so many different people with different ideas of what is fun.
Myself I can't stand the F1 style tracks with wide roads and large corners,
while I know many others do.
I think a good idea is to segment the game off a bit, into race, drift, drag, cop&robbers etc... I think this should be implemented into the multiplayer server list as filters.
Then develop speciffic tracks and maps for each segment.
Maybe a city map for cop&robbers. Race and drift go pretty much hand in hand track wise, but I want a bunch of twisty, narrow tracks for drifting purposes. Several airfield layouts for drag, and creating own layouts, as well as purpose built drag stadiums. We would need some good WRC rally courses for the ppl who like off road. Snow would be kewl, for use with studded tires.
For detail on the tracks themselves, I'd like a tad more realism, like wet spots,
uneven surfaces, varying asphalt quality stuff like that! Like another person said, even places where the course has "rubbered in".