IF MK gets banned, he will not start the ball rolling. Snake will NOT get banned. And I'll tell you why. Snake has bad matchups. He is beatable. At the first tourney I ever went to, I beat a Snake in friendlies with my Sheik. He ***** me the first game, but I beat him the second because I had learned how to approach. Snake isn't too hard.
MK, on the other hand, is hard to beat. He has so many options, lightning quick high priority options at that, that beating him with anyone below high tier is an extremely rare sight. He is crippling the metagame of lower tiers. After my first tourney, I decided to pick up Diddy. I did it to counter MK, who even though I didn't play one at that tourney, I knew I would fight one sooner or later. And I knew that I would not win with Sheik, who, otherwise, doesn't have too tough a time with other high tiers. Now I find myself going Diddy more than Sheik, because it is easier to win. I won't rep Sheik as much, I'll rep Diddy instead, who's already top tier.
TL;DR MK hurts low tier metagames. Ban him.