Mostly, I'd like to see more cars from racing series. ALMS, DTM, BTCC, SPEED World Championship, V8 Supercar, etc. instead of the manufactures like daihatsu , Dome, Nike (come on), etc. And newer cars would be nice too. I've driving a lot of the older cars, and my ginetta G4 is something i like to just take out once in a while, but anything before 1975 (including muscle cars) can be chucked IMO.
but the thing i'd like to see them most is Polyphony Digital to go after the licenses for Porsche, Ferrari, and Lambo. A Gallardo or a F430 ALMS car would be REALLY nice to drive.