The question is why wouldn't you?
Unless you have no intention on getting an NX.. waiting for a several months more for the Wii U version is not the end of the world. Launching the game on a new platform will bring in more sales and (new) interest in the series thus making the long development cycle for the game more worthwile.
Also, I intend on getting on Nintendo's next console so I get to play the better version of the game as well :P Assuming Zelda U is actually coming out on the NX of course.