Mario Kart 8 producer Hideki Konno has confirmed that there won't be a track/course designer for the upcoming Wii U game.
Konno did acknowledge that the concept of user-created courses is "a fun feature" and something that he's been interested in "for a long time", during a GDC roundtable. The main reason for the lack of the much-requested feature is how tough creating courses are, as he noted that "we have a lot of confidence in our ability to do so, but we understand what a tough challenge it is to create those courses."
Konno feels that the team aren't a point where they are "able to do that at a level that would satisfy anyone, myself included, or the customer". That said, he still believes that if Nintendo can come up with "a solution and implement in a way that makes everyone happy, or we think will make everyone happy, we'll come back to that issue and maybe re-address it."
Do you think a track building feature could work in the Mario Kart series?