While NX was not yet given a date, internally they definitely had a launch plan well over a year ago. With that in mind you can state the launch was delayed or rather their plan was changed prior to a public announcement.
I believe the plan was moved from a holiday launch to March for a few reasons.
Data:
1) Consoles have been launching in holidays for a few gens now because its more lucrative.
2) Zelda U was definitely NOT going to be launched without being at same time on U/NX.
3) Zelda U was originally delayed to be NX-ified from a 2015 to a 2016 launch.
4) Nintendo announced a new platform called NX in early 2015.
Questions:
1) Why would they move Zelda to "2016" if they had not been planning for a possible NX 2016 launch?
2) Why would they tease NX so early in 2015 if they had not been planning to release in 2016?
Conclusion:
Nintendo intended to launch in 2016. However, game and possibly hardware development was not at a level where holiday 2016 was achievable, therefore they moved it to March 2017.







