I mean... if Koei Tecmo wants to be cool and release Dead or Alive Dimensions on Switch and then just add Hayabusa to Smash as a tie-in to that, that'd be great. Then Smash could add like, some obnoxious story about how DOATEC wants to engineer the perfect fighter and captured Mewtwo, a character already genetically engineered to be the perfect fighter so they could make a Phase 4/Alpha-152 version of Mewtwo, and the only thing that can stop them are Ryu Hayabusa, the DOA girls, Geno the doll, and Incineroar the pro wrestling tiger. It'd be truly insane.
It's also probably not gonna happen
I don't think the ninja man is coming. Nor the ninja girls (or any of the other DOA girls, cool as that would be). I feel like there's something to that whole "Koei Tecmo won't work with Capcom" thing, and I know people wanna talk all Fire Emblem: Three Little Pigs, but Fire Emblem is a Nintendo property, Nintendo can do what they want with that. Warriors/Musou isn't, so no Hyrule Warriors music or whatever in Smash, no Hayabusa either. Would LOVE for that to change.
What I'd ALSO love if next week could be Smash week: Last week was Mario Anniversary, this week was Hyrule Warriors: Legend of Calamity Jane the forgotten cartoon with the gray skinned girl... next week Smash maybe?