I just thought of something. What if Zelda U got delayed because Nintendo wanted to make a sequel for it a year or two after it dual release for Wii U and NX? This game has to be Nintendo's most expensive game since SSB4 but with even longer development time so Nintendo may try to use as much of that game's engine as possible. Kind of like how Majora's Mask borrowed so much from Ocarina of Time. You may think it would be weird to delay Zelda just to have a sequel for it but I think it makes a lot of sense if they used that time to make the stories for both games to be really great. Who knows, Nintendo may even try to make a trilogy out of the Zelda U story like Square Enix did with FFXIII to get as much out of Zelda U's engine as possible.