To be honest, making the game go from duel screen to one screen wouldnt require that much re-tooling and the game would give NX launch a big kick. I mean, I know the Wii U isn't dead yet but it all-but is dead isn't it, commercially.
I'm happy to play Star Fox Zero for whatever console it appears, but from a sheer "lets make our next console a hit" viewpoint, any help from already-made games that havent come out yet would massively help, rather than spread resources even more thinly across 2 or 3 consoles (wii u, 3ds and nx).