Why would you use classic controller when you can use gsmepad or wiimote?
I've been over this before but...
1. I try to avoid using the Wiimote if I can help it, unless the game involves pointing at things (which is all the Wiimote was ever good at).
2. The gamepad is just too big for my hands (to the extent that I have to completely reorient my hands w/ games that use both sets of triggers), & I don't like that screen ALWAYS being on if you're using the controller. In a game like ZombiU that's built around the two screens having unique content you need to constantly be using, it's fine. But in games where all it's doing is mirroring the display I already have on my TV, I find that screen incredibly distracting.
The Pro Controller is smaller, lighter, & it doesn't have a screen I frequently don't need. Yeah, I think Nintendo should have at least provided the
option to use it in NSMBU. Frankly, it should be supported in every game on Wii U that doesn't use the Gamepad's screen for a vital purpose. Let the player choose how they want to play your game.