Pretty pointless question. I somehow doubt Nintendo would ever let any of their mascots in a game where they’ll quite literally get ripped to shreds and have all sorts of violent actions used on them. Only possibility would be Bayonetta, but even she wouldn’t really fit in.

Yeah...this is the only crossover I would think would work.  They're almost from the same universe.  I don't think any of the characters in Smash would like to know about fatalities and people getting their hearts removed from their bodies while they're still breathing.  

I’d be cool with Raiden!  Him vs. Pikachu.  😁

Always possible, with a lot of work, to make unique Finishing Moves for characters to use against Bowser, that are slightly less brutal.  

Oh well.

Ganondorf vs Shao Khan!

I think that from a franchise perspective, the series is old enough and has stood the test of time well enough/is currently relevant, that a character would be deserving to enter SSBU. Add to that the timing of SSBU and MK11 and it’s not a bad marketing idea.  We’ll see.

That’d be cool.

They can put Kirby in MK. Smash Ultimate prooved Kirby is the most powerful video game character ever. No need for fatalities because no-one will beat Kirby anyway.

I don't really see Nintendo adding one of their characters to MK, maybe costumes at most but not characters, kind of like Tekken Tag 2 on Wii U.

MK in Smash? I would be cool with it, the series is pretty iconic and it has presence in Nintendo. Deserves it a ton more than Persona for sure.

Sure, any crossover would spark interest but this one comes down to one aspect for me and it isn't violence. Gameplay. Nintendo takes it extremely serious while the guys over at Neatherealm care more about graphics.
I was once a strong MK supporter. I grew up playing UMK3 and in the arcades. Trilogy, although ran on the same engine, was the mark of that franchises downfall.
I was just saying how MK is easily one of the worst examples to make the 2D to 3D transition. Mario? Arguably the best.
Now if a kombatant made his or her way into Smash, the whole nature changes. Nintendo, imo, would most likely show NR how it's done with smooth animation that actually makes sense.
MK needs to reinvent itself in a more fluid and polished animate before even considering making guest appearances.
Especially in a game produced by the masters.

I almost never like cross over characters because it just doesn't make sense. Geralt in the new Soul Calibur is the one exception, because I bought the ridiculous explanation of it.

I would love a MK character in Smash. Not the other way around. Don't feel the need to see Nintendo characters get ripped apart.

Scorpion and sub zero in smash
Bayonetta and Mythra or Pyra in MK11

Neither.
MK is not MK without their fatalities, and so would be out of place in Smash.

I don't want to see any Nintendo character fatalatized either and I doubt many companies would want their mascots/brands being fatalatized as well, so disregard Nintendo, I don't see many companies wanting their characters in MK period.