People have been using the controller for more than 10 years across Melee and Brawl and countless Brawl mods. Switching now, just for the WiiU is not an easy adjustment and the WiiU allows 1080p play from the console which cuts out the input lag usually brought on due to the Wii only outputting at 480p through component.
Then it is just a case of "being used to it". The thing is, I played Smash Bros 64 since launch but didn't get Melee (and a GameCube) until a year later, and therefore had 3 years of prior experience using an N64 controller for Smash Bros. Perhaps this resulted in myself not being so married to the GCN pad for anything Smash Bros related?
Ah, well I find the Dpad on the GCN pad very lacking (try playing the Japanese "Nintendo Puzzle Collection" with it) so even the original CC is a great improvement with it's Dpad, not to mention I never owned a SNES so I need a quality Dpad for my SNES VC games.I've just always liked the Gamecube controller; to me it was the perfect combination of the SNES and N64 controllers.
I never had a rumble pack on the N64, and I got a Wavebird when I got my GameCube, so I never got attached to rumble. Heck I even turn off rumble on my wiimotes to conserve battery life.The CCPro is an improvment over the original CC, but it unfortunately lacks rumble.