Nintendo needs Smash 2014 for the holiday boost and Amiibo. Looking at how far along the game is and the fact that all the characters are already set for 3DS anyway there's no reason at all they can't make a November date.
Nintendo needs Zelda 2015. It's clear they have no other relevant title of scale in development to take its place should it not be there. They can obviously do it, they need to have learned from their HD development mistakes by now. 2016 would mean it launches on a dead console with no momentum and sells accordingly, in my eyes. Hello guaranteed lowest selling console Zelda game in history.
They'd have to have no interest in their own success if they delay. They've already delayed enough and I would be quite spiteful as a fan if they pulled two five year gaps in a row with Zelda, particularly if I felt the wait wasn't worth it.
