I think 2016 is actually the more ideal window to launch.
They can bring Legend of Zelda to the NX that way, and it will be a huge boost to the NX launch, just like Twilight Princess was to the Wii.
If they miss that window, then the next Zelda probably isn't coming till 2020, so that will be a looooooooong wait.
For 2016 they could have Zelda and then quickly followed by a new Mario in quick succession. Also whatever Retro's new title could also be in the first six months since they are also due. And then you can have Animal Crossing slide in comfortably 8-10 months post-launch.
And having Dragon Quest XI for Japan would be big, this is a real DQ game too, not like the online DQX that Wii unfortunately got. And maybe Square-Enix will also be willing to bring Kingdom Hearts III and/or Final Fantasy XV too and those are all due to drop in that 2nd half 2016/1st half 2017 window.
It's fairly obvious they have pulled some punches with the Wii U and are saving those for the NX (ie: "real" Animal Crossing, no second 3D Mario for Wii U), so I'm not worried about their software launch.
