- Replace Follow the Leader with a new elimination mode in which after each lap (or after a certain period of time), the player in last place gets eliminated.
- 3 Strikes Battle: Add the ability to change the # of lives from 1 to 20. If this is done, the mode should probably be renamed to something else besides "3 Strikes Battle".
- Add more soccer arenas and improve the existing ones. Forest, Oasis, and either Cosmic or Cosmic II would make good additions.
- Have AI be able to detect and avoid obstacles like the moving spike balls from New Fort Magma and detect and drive over speed boosts.
- Rebalance the three kart classes so that heavy and medium karts don't have a huge advantage over light karts.
- Make the banana hazard a collectable powerup that you can place behind you.
- Replace some of the outdated or terrible audio tracks with new ones, specifically "Overworld", "Boom Boom Boom", "Penguin Party", "Hacienda", "Race Summary" (including 1st place and lose theme), "Win Theme", and what plays at the start and end of the race and the start of the final lap.
- Make the Cartoon skin the default skin but keep the old legacy skins.
- Move all soccer arenas into a separate repository
- Make all battle arenas available in singleplayer (or if this isn't possible, add a warning if a battle arena isn't available in singleplayer)
I want to say replace the bananas and bubblegum powerup with different powerups or hazards that function the same since I always thought having bubblegum as a powerup shield was ridiculous and in real life, touching a banana doesn't cause an anchor or parachute to appear behind you. But I don't care what they do.