Snaking + rankings/matchmaking + item switch
People who complain about snaking are complaining that someone else was better than them at the game, which is absurd. Mario Kart DS is the most competitive and skill-based Mario Kart ever made. Highlight of the series for me and my friends. It went beyond being a time-wasting party game and was actually a competitive thing for us for a while.
Item switch would be great. Turning off blue shells would help balance the gameplay, and even just limiting it to green shells and bananas would be fun.
And to keep everyone from bitching about losing, it should have tiers/ranks like any other competitive multiplayer game. Snakers will get grouped with snakers. Non-snakers will remain low and can race with each other.
Or they could split it up into competitive and casual sections.
None of this is going to happen. I still can't believe they got rid of moving the joystick left/right to gain sparks in Mario Kart Wii. It was a series staple until people bitched about Mario Kart DS. Did it return in Mario Kart 7? I'm assuming it didn't.
Also, +1 track editor, tons of tracks, classic battle mode, and omg Bob-omb Battlefield idea is the greatest thing I've ever heard.
I missing snaking solely because it was the best method to dodge a blue shell in MKDS. I hate having to rely on getting a mushroom in the new games and the timing is pretty bad.