Yesterday, Zelda series producer Eiji Aonuma issued an apology and announced that the Legend of Zelda for Wii U will not be appearing at E3 2015 and will not release in 2015 at all. By way of explanation, he said new and exciting gameplay possibilities arose during the development of the game. So significant were these ideas that they decided to push out the release date so they could fully explore them. Nintendo has never been shy about taking as long as it takes to make good games. However, in recent years, they have adopted a strategy where they avoid announcing or showing titles until they are very far in development, or even ready to release, to avoid disappointment at missed deadlines. The fact that they so publicly promised the game this year, then delayed it, I think speaks to the significance of the gameplay innovations they are working on.
There's no telling what this means for Star Fox, since Mr. Miyamoto stated it would come out before this Zelda game. Hopefully we will still see this one at E3.