I'm saying that Nintendo had too many types of wii controller with the wii remote and nunchuck coming as standard, the Motion Plus as an upgrade to that, then the Classic Controller (and some games support Gamecube controller use). If you were developing a game, which controller do you focus on?
Publishers want to reach as broad an audience as possible and I'm sure devs prefer to work with standard controls. At least with the standard wii U the controller has all the buttons required to make ports of standard games easier and with as broad a userbase as possible. If the wii U gets a decent number of users it should see better 3rd party support than the wii did.