we already talked about making an alternate controller becouse it would be to expensive with another master controller, and i think i got an idea that maybe would work.
release an wii u controller.....LITE!!! it wouldnt have the camera, sensor bar, mic and other stuff a second player wouldnt need.
i made a pic of my idea together with @Nintendofreak247's idea with mario kart.

However, i dont know if removing some features would still make it affordable, what do you guys think?
[INSERT OPINION HERE!] :PPP