I wanna see way more Aussie cars - There is more to Australia than the V8 supercars and the HSV W427!
I'd like to see them include more classic muscle cars, like A9X Torana's, HQ Monaro's, XY Falcon GT's, FJ Holdens - the list goes on! It would present a huge number of race opportunities, like re-creating a classic Bathurst 1000, or just a nostalgia-type muscle car race for instance.
That brings me to my next thing - Include some Aussie tracks! We've got loads of world class tracks here like Eastern Creek, Mt. Panorama, Philip Island, Sydney international drag way - and that's just a couple of them, I can think of at least 10 others which would be good!
Including some Australian tracks would actually make using the V8 super cars feel realistic, as they'd be racing on home ground where they're actually used in real life, not chasing down some dodge viper on Sebring, which I don't think has or will ever happen in the real world!
I'd like to see a couple of American hot rods - things like late 20's and early 30's Fords and Chevy's, these were the cars which started the whole nascar scene, so it might be a bit of fun doing an original race like that.
It'd be fun to modify them with classic flathead or y-block engines, as well as taking them round a twisty circuit or somewhere like Fujimi Kaido, or maybe a few dirt racing tracks! (like this -
http://www.youtube.com/watch?v=2yd-0-eCZPY ). The hot rod scene is pretty big in Japan as well as Germany among other places so to people in the know it would feel somewhat realistic, if you don't know what I'm talking about check it out here -
http://www.youtube.com/watch?v=DNYJOZQsAKg.
More content available to those who can't afford xbox live! That'd be real nice!
I wouldn't mind seeing some (not an entire world, just SOME) open roads, such as the Transalpina Highway in Romania or like the road that can be seen in that home space. It would be good if you didn't want the hassle of driving a race, and just wanted to drive at your own pace on a mountain road somewhere...
More focus on drag racing! More realistic pre-stages would be a nice change! Also the ability to build a gasser, or maybe some top fuel or doorslammer cars. User controlled pre-race burnouts to gain traction for take off would be a nice realistic effect.
Changes in weather would be nice, or night time driving.
I'd like more freedom with the cosmetic side of modifying things. Sort of like need for speed underground 2, how there was heaps of spoiler style choices, and roof scoops, hoods, tail and headlights etc. It's not bad in F4, but with some cars you only get one choice of rear wing, and there are sometimes no different options for hoods or front splitters...
I know it's meant to be a simulation racer and all that but a little more variety in body modifications for the less commonly used cars would be a welcome thing for those who want that super customised ride.
I'm pretty sure I could think of other stuff but that'll probably do for now!