I have a GameCube, and the lack of BC on this new Wii still makes it seem like a deal-breaker for me for some reason. I don't know why though; I don't think the BC Wii's actually do anything special for GC games (unless they actually run faster/smoother?). Do GC controllers work with BC Wii's and not these new ones?
The only benefit to playing GameCube games on the Wii is that you can buy component cables for the Wii and run certain GameCube games in 480p, instead of hunting down the super-expensive GameCube component cables.
Also, if I recall correctly, this new model of Wii got rid of the GameCube controller ports, too.