The leading argument for porting WiiU games to the Switch really has been
"This game hasn't earned the audience it deserves on the WiiU. Give it another chance on the new Switch platform. When a new audience of people play it, sales will be great."
Very true of course for many of WiiU's best 1st party games - but maybe also for the WiiU's best 3rd party game as well.
With very little doubt, the game that is probably most criminally undersold on the WiiU is Rayman Legends. Even as WiiU's best 2D platformer, it hasn't even sold half the same measure of WiiU's other great 2d platformers. Sure it was ported to 360, PS3, X1, and PS4 also but sales of Rayman Legends as a multi-plat are still only a mixed success. Sales of the game in Japan in particular are inexplicably abysmal.
Rayman Legends is truly a fantastic game - one that not only stands shoulder-to-shoulder with Mario and Donkey Kong Country - but in some ways also stands above those games as perhaps the best 2D platformer in the past decade.
If we're bringing the best WiiU has to offer to Switch, Rayman Legends naturally fits in that same category. Further, reintroducing the title on the Switch ought to help reignite interest in the title on PS4 and Xbox One too.
I predict NX launches in 2017 - not 2016