Listen.
I'm gonna be part of the minority of speaking here.
But I just can't see Mortal Kombat in Smash (not like I haven't been abundantly wrong in DLC in particular)
And part of it is the amount of raw violence and gore that's at the core of the series's identity
But...
At this point, Smash has had 7 3rd Parties.
6 of which are some of the inarguable icons of gaming. Faces of their genres.
being the biggest oddball. Arguably a very iconic face OF action games for the kind of personality she dominates and sexual tone to the way she moves, fights, and speaks.
What got Bayonetta in? Overwhelming popularity in Europe and NA that most of the community scoffed at; which isn't to say she didn't have some notable following in Japan but it wasn't nearly at the same level. Even in the small view of the Source Gaming poll she cracked top 19.
Mortal Kombat is something that I've heard just about nothing of when it comes to following that leaves the states and it being something that doesn't have much of any following in Japan in particular because of my knowledge the culture there is as strict about violence as the states are about sexual content.
And the fact that the only thing that the series has made its name FROM is the graphic violence that was the main catalyst for the ESRB to be formed in the first place....
It just doesn't seem right to me and even if one of its fighters get in it probably still won't.
I'd expect Soul Calibur or Tekken to get their foot in first, at least.