Don't worry, it won't be long until this is possible on the Switch. We're already moving in that direction anyway.
Really doubt that we will see Kratos, Nathan Drake or Master Chief for Smash in the near future.
Haha...I'm sure you're right...but the concept you're referring to seems a tad more far fetched, no? And I wouldn't count anything out at this point with the positive relationships Nintendo and Sakurai seem to be cultivating. There's no denying that Nintendo is having the biggest gaming party of all time over on the Switch with Smash Bros and I understand why all the cool kids from the other consoles want to come see what it looks like from the inside. I can't fault you for that. But thinking you could just move that party wherever you want and repeat the magic seems a bit optimistic. And as much of a stretch that it seems that Nathan Drake, Kratos, and Master Chief would come over to Nintendo's house for a fun romp, I think it's even less likely Nintendo will let Mario go galavanting around in another fighting game on another system. Some random turn based tactical fighter, sure...but a Smash clone. Not a chance.