Well since the game allows Amiibo's support to change Mario into other characters, Nintendo should have some of their other non Mario teams make some levels and release them in the future. Like here's some levels from the Zelda team, some from the Animal Crossing team, here's some levels made by Sakurai. That would really be interesting to see.
Actually that last one could happen since they used Sakurai to help show off Wario Ware: DIY after that came out as well.
That would be a great way to help keep attention to the game months after release. Hell, maybe even contact some third party game designers like Kamiya to make some levels as well. Lots of potential when you think about it.