Level editor Would work like the THPS series could work.. or Halo 3's sandbox.. Unpacking and dropping a library of meshes available from the game's library.
There could be set backdrops.. simple themes..
* Factory
* Neighborhood
* Hills
* Snowy Hills
etc etc
Car/Character MakerSadly I have to mention TM4..
you have to admit.. 'THEY TRIED'
Simply.. I wouldn't mind taking some of those elements and advancing it.
In order-
1. Small, Medium, Large.. or light, medium, heavy..
This leads into types that size and weight..
Monster Truck, Postal Truck, Semi, Sports Car, etc. etc. maybe add some modern looking and old cars.. etc. wacky stuff that also can be unlocked from story mode.. or playing.
2. Next up is advanced look customization..
Change the color, add decals, add props. (Has a limited bar)
3. Next is the basics.. Speed, Handling, Special..
Selecting the speed is first.. which then leads to a selecting the handling.. and then finally.. the special and this is last because we all know speed and control effect the special.. so selecting them first will filter the specials.
4. Advance Special Customization- Color, sound, speed, damage.. all is customizable BUT again filitered from previous choices.
5. Final Section.. Character/driver profile.. etc.
Webcam/harddrive photo upload..
Might be possible to have a custom text ending like TM1.
SAVE AND PLAY!!