For point 2, do you mean the choice of stages to vote on? I haven't played online much so i haven't noticed. "Random" is always an option, though, so every stage is always possible, but at the same time the amount of stages you can vote on is delightfully limited.

Mario Kart TV as it is now is lame. You should be able to edit Mario Kart TV footage to the degree that people have been doing on YouTube directly from Mario Kart TV. That means songs, cutting footage, zoom, distortion; everything.

They should patch in a second driver.

They need to remove the coin item and make using shellsbananasetc the same as before.

Nah, the removal of shell/bananna stacking is good thing, it makes the guy coming first less invincible. 

I've noticed a few niggles here and there (aside from battle arenas which is a huge omission) so I probably forgot a few:
Display race times
Option to show map on TV
Option to show only gamepad-player's screen on the gamepad instead of mirroring the split-screen TV image
Change position no. to "?" during maze section of Yoshi's Valley
Option to show more detailed kart stats
More battle options; stock instead of points especially
Battle arenas, preferably as free DLC

- fix connection issues
- disable fire hopping and reset the time trial lists (will make some people mad, but better sooner than later)
- decrease the chance to get the coin item (as long as it doesn't overpower the first place)
- more options in MKTV (better angles for Luigi's face)
- course map on the main screen
- add GameCube controller support for those who prefer wired controllers (when the adapter releases)

Map on screen or at least positions and what items they have on screen. I want to know who has that red shell.

People complaining about the coin need to stop. The coin gives you a speed boost and if you really need an item to feel safe in first I feel sorry for you. If anything they should at least make it so that you can't get a coin when you not in first because then the coin doesn't help much. Also every time I get a mushroom the people in front of me get 3, like what's up with that. The items need a better randomizer or whatever its called.

For me the connection problems already are fixed. I couldn't finish a single race last weekend, but just now I've played about 30 races online with my sis and the connection didn't drop a single time.