Colosseum wasn't that bad, people. At least we had a Pokemon RPG on a console, and the shadow Pokemon thing was at least kinda fun (Thought irritating at the same time). I would be cool if they made another one. Though I doubt they would release it. Also, a Pokemon Snap Wii / DS would so awesome (Has to cover Kanto - Sinnoh, be long, lots of Pokemon and unlockable areas, and lots of extras)!
A cel-shaded Zelda game on the Wii would be cool. Wind Waker was really good, and I don't think Phantom Hourglass really made up for it... And it would balance the "Dark side" of Zelda we got with Twilight Princess.
Super Paper Mario was good and all, but it was short, easy, and boss battles were pathetically repetitive (And easy). I would really like a Paper Mario RPG, since those were pretty cool. And if not, at least a new Mario RPG.
Pikmin 3. Come on, who doesn't want more Pikmin? I would love for them to finally make another one, and Nintendo knows fans want more...
New series. It's been since Pikmin since we've gotten a new series, and Nintendo kinda needs a nice knew series to start fresh again.
Resurrection of a NES Nintendo title (Donkey Kong Jr., Ice Climbers, Kid Icarus, etc) on the WiiWare.
Regarding the Wii, in general it needs more RPGs. >_> At least we are getting ToS2, but I really want ToV, haha. (Just gonna buy a 360 someday soon anyways).
DS is still going strong, and more and more RPGs and such are coming out which is a huge plus.