1)Voice communication as well
2)More games online!
3)A better online community feel
5)More in depth profile mii stats (like game stats for your miis...kinda like xbox 360 achievements)
6)Each game should have unlockable bonus costume pieces for creating mii's. Like if you beat Mario Kart on the hardest level with mario you get his hat or something. It would drive people to play more to get more.
7)ONCE AGAIN..................MORE ONLINE GAMES!
I'm upset that I cant play wii sports with you guys...