For the first time since Link's Awakening, a Legend of Zelda game will have the option for an alternate ending. Nintendo Life says Eiji Aonuma teased as much in a recent interview, and it would appear 100% completion is the key to seeing the ending...
"Yes there is an alternate ending, there is a certain criteria you have to fulfil to see it. Essentially, you do some specific things and you'll see a different ending."
It's unsure at this time just how substantial this ending could be. For example, while Link's Awakening presented a different ending to players who completed the game without dying, Majora's Mask and Spirit Tracks had small and very subtle changes to the end game depending on tasks completed in the games.
I'm tempted to think that with the work put in this game to change the formula of the typical Zelda game they went ahead and made a full fledged alternate ending, what do you think?