Agree with Toby, if all the ACT players used MK next tournament it would make little to no difference, if anything I think you would place worse. People have way to much experience in the MU, while MK is easy to use because he is crazy broken you still need to understand what he can do and how other characters can beat him. I'm willing to bet I could beat the majority of you guys using Ike if you played MK because you don't know how to play the character. Like when Alzi played MK against my Ike I 2 stocked him. The same thing would happen if you played Toby, although you would get three stocked. I think Nanda could beat my Ike though since he should understand how to play MK by now. The same thing applies to all characters really and MK is like a double edged sword you have the advantage of a crazy broken character but the disadvantage of everyone knowing the match-up and knowing it well. You will have to main MK to place well with him. Yes I think that in the long run scabe and silfa would place better using MK. Also Toby would 2 stock Nanda.
TLDR: If you use MK next tournament you will fail.