My small list;

- No bikes (it's mario KART)
- Blue shell like the one in MK64 (it can hit others as well if they don't watch out)
- Free for all battle, why they left that out from the Wii's MK is a mystery
- 5 player could be possible
- Online shouldn't have 100cc in the mix
- 4-player split screen AND online at the same time, now that would be awesome
- Coins should be there

I don't undetstand the appeal of Battle Mode either. It's incredibly random and doesn't compare with nailing opponets with items in an actual race. :P

Do everything Mariokart DS except in hd.
Just improve online and keep 12 players, bikes, and tricks. MK DS and MKDD were the only games to get battle mode right and shine runners is also cool. Keep story mode, that was dope.

I just want a cup holder for the WiiU wheel..

I can already see this coming --

Standard GP for classic Mario Kart

And a "new" Double Dash style mode, with dual-racer karts. One player steers with Wiimote, the other player in the back has the Wii U tablet and mans a "weapon turrent" and has to spin around and use the Wii U tablet's gyros to see other racers/obstacles come from all angles and shoot them away. Could also hit speed boosts this way. Stuff like that.

I'm definitly excited to see the next Mario Kart in action for Wii U, between the HD, improved online system, and implementation with the gamepad. Nintendo needs to implement the XBL style of the online complexity, particularly with games like Gears 3 and Black Ops 2. That sort of online depth with a game like Mario Kart would be simply too epic to even imagine. While I'm holding off on the Wii U for now, the next Mario Kart will probably be the game that seals the deal for me. I have a feeling it will be amazing.

Snaking

I love battle mode, just wish there had been more stages and few more options with it

I agree 100% with the OP, I'll add a few points as well.
-60fps is madatory on 4player split-screen
-Fix item managment. Whith the exception of MKDS, after MK64 I feel every new game has done it worse than the previous. More specifically, less blue shells and don't make the player lose his items when he gets hit.
-Try to make the handling easy to learn / hard to master, more like in MKWii and MK8, unlike double dash and MK64.
-Make the battle mode fun again, and since they are it try to add some new game modes as well.
-Make avaliable for sale all the old tracks from the previous games as DLC.

Get quality game testers to make sure that there's no game breaking shortcuts.