http://uk.ign.com/articles/2013/06/20/dont-get-your-hopes-up-for-f-zero
So, they know we want a new F-Zero yet they don't want to make one because they can't think of a never-done-before gimmick (and Mario Kart 8 stole its anti-gravity shtick). Here's some news for Nintendo: everything that can be done, probably has been. Get over it and try to find new ways to adopt already-seen-but-maybe-not-in-F-Zero stuff, like Trackmania's track editor, Grid's time reversal mechanic etc.
Nintendo's execs, like Miyamoto, don't seem to understand that new gimmicks aren't always necessary for new games. F-Zero fans (alongside fans of StarFox, 1080 and others) have been so starved for new material for so long compared to Zelda and Metroid fans that nobody would mind an HD downloadable re-release of X and GX's tracks with 30-player online support.