Why not update the Wii system on newer Wiis and Wii Us to accept the Game Cube Controller Port Adapter. That's a far better use than SSBWU, especially considering they make GC style controls that plug into a Wiimote, ones authorized by Nintendo.
I heard Nintendo was taking back Wiis without Game Cube ports, because nowhere on Active Life or Wii systems was the incompatibilty mentioned. Dance Dance Revolution was severyly hampered by this, and real early joypad games like Metal Slug Anthology were made crippled by the lack of GC ports.
If you look at the list of Wii games hurt on a Wii U, all of them have to do with a lack of a GC port. Metal Slug Anthology was made BEFORE Classic Controllers were thought of. If you want to advertise 100% compatibility with Wii games, this is the solution. I understand Game Cube GAMES won't work on Wii U because it needs an 8 cm disc loader.
Finally visit my post on exercising on the wii u to see future potential of the game cube port adapters.