(obvious Bowser Jr. and Koopalings aside)

I have doubt that we will see Wart or any RPG characters (including the elephants in the room Fawful and Dimentio, though I think Fawful would have a higher chance imo) but I think Tatanga would be an interesting choice, because I don't see much issues with him being included since like Foreman Spike, he comes from older titles, both of which are platformers to boot. They might introduce Daisy down the line so having Tatanga appear would be only fitting.

But really, if any RPG character is ever confirmed and I will SCREAM.