Its announced Wii u WILL NOT USE GAMECUBE CONTROLLERS!
It will ALSO BE UNABLE TO PLAY GAMECUBE GAMES=no melee
Source: http://www.gamepolitics.com/2011/06/08/wii-u-dumps-gamecube-controller-amp-game-support
Second Source just for that extra info if you didn't believe the first one. http://wiiugo.com/wii-u-drops-gamecube-backwards-compatibility/
It will ALSO BE UNABLE TO PLAY GAMECUBE GAMES=no melee
Source: http://www.gamepolitics.com/2011/06/08/wii-u-dumps-gamecube-controller-amp-game-support
Second Source just for that extra info if you didn't believe the first one. http://wiiugo.com/wii-u-drops-gamecube-backwards-compatibility/