This won't change a damn thing.
People won't buy WiiU simply because some few games will support GC controllers.
I agree. I face palmed when I saw his comment.
Also, I don't see why people are so fanatic about GC controllers,
WiiU Pro controller is a thoushand times better.
Well at this point, they're only usable for Smash. This is a big deal for quite a few reasons. You have to remember that many Smash players have been using this controller since 2001, so it's more comfy to them then anything else. Part of it is possibly nostalgia, but another part is the muscle memory associated with it. Aside from that, the three-button-row of X/A/B is reminiscent of three-button fight pads that a lot of fighting game enthusiasts like to use (that's why so many people preferred the Genesis over the SNES for games like Street Fighter).
Also, having a wired option is a must for huge tournaments. Otherwise, all the wireless signals would interfere with each other, which is a real problem in Smash tournaments when people use wiimotes. The same problem would apply to pro controllers. There's also the issue of less lag with wireless, but that's dependent on the individual.
Aside from that, I think the pressure sensitive triggers are rally comfy, the shape is ergonomic, the way the four buttons are set up in general are nice and streamlined (every button press is only one small twitch from the center A button; no nonsense having to hop from A to Y), and I find it to be the most comfy controller I've ever used. Even a friend of mine who never owned a GameCube thinks it's really comfy, so it's not a matter of nostalgia in that regard.
That said, the GameCube controller isn't perfect. The dpad sucks and the right stick is awful for shooters. The pro controller is certainly better for general use and especially VC games. But for Smash, and for all the GameCube games that were designed around its unique button layout, I think the GameCube controller is the best controller by far.