One of the more enticing bits of info to come out of Nintendo's showing at the Game Awards was that the new Star Fox game for Wii U will supposedly launch before the new Zelda game. This is surprising, considering the E3 demo of the new Star Fox looked rather rudimentary, whereas Miyamoto and Aonuma were showing off a beautiful, polished demo of the new Zelda at the show last night.
That said, Zelda games are typically several orders of magnitude bigger than Star Fox games, so the new Zelda is probably taking longer to finish. I wouldn't be surprised if Star Fox is a big summer/fall release alongside other tentative 2015 titles like Xenoblade Chronicles X, with the new Zelda being Nintendo's giant holiday release.
When the new Star Fox was announced at E3, Miyamoto said Nintendo was looking to partner with a third party studio to develop the concept, like Namco-Bandai helped with the new Smash Bros and Tecmo-Koei co-developed Hyrule Warriors. Perhaps Nintendo has teamed with a third party already, but the question remains, who?