Its almost certain that Switch will have more Wii U ports, so you done with Nintendo for good right away.
At this point Smash 5 is definitely possibilite, I mean they can merge hole content from Smash Wii U and 3DS, bring some new content also and call that Smash Bros 5.
they better not port smash 4, it was on 3ds and wiiu thats enough
Muda Muda Muda Muda Muda Muda!!!!