Miyamoto Says sorry for zelda Botw delays, he expected it to be out in 2015.

[S.T.A.G.E.]

PR babble, I'm sure. I'm sure they sensed the anticipation of Zelda and decided to launch it with the nx. It would've cannibalized potential sales for the nx in the beginning. If you launch both together people can decide to make the jump knowing it's over for the wii u.