I'd love to see a Golden Sun game on the Wii. But, otherwise, just a few 'proper' turn-based battle type RPG's. There were never many of them on the GameCube and I hope that changes on Wii. I'm all for new types of battle systems every now and again, but strategic turn based systems, ie FFX, have always been my favourites.
And I'll be completely pissed off with Nintendo and GameFreak if they don't release an actual Pokemon RPG on the Wii at some point. There is absolutely NO reason why it can not happen now. They always gave the excuse that the Pokemon games were about collecting, sharing and battling against other people. Wii has WiFi, so we can still do all of that. In fact, they could even make it into an MMORPG if they would be really ambitious for once.
As stupid as it might sound, I'd like to see a Luigi's Mansion type game on the DS. Also, Mario Party should be moved to the DS, it is MUCH more suitable for handhelds than full consoles, IMO.
Of different franchises, naturally I'd love to see Final Fantasy on the Wii. I'm not talking about Crystal Chronicles either. I wanna see Final Fantasy XIV on the Wii. Sony has had six of the last seven FF games, it's time for square to bring it back to Nintendo's home console.
GTA would be a good addition too. It's not a game for everyone, but it'll definitely guarantee sales.