KBs, if they stay, should be specifically on counter hit and set up combos. The player on the receiving end shouldn't be able to use breakaway on KBs. I'm envisioning them like SF Vs crush counters. I want more actual footsies in my MK.
FBs are fine in the concept of keeping a comeback mechanic. I get that almost every single contemporary fighting game has a super or ultra move of some kind, and these are MK's equivalent. I, however, want it back to being tied to the meter. I get that it wasn't much of a choice in MK9 and X when it came to meter usage. You saved it for the breaker, so supers, FBs, x-ray, whatever it's called, have to be stronger in some way. Maybe have less scaling, making them more used as combo enders? Something like that. It shouldn't just be "oh, I need to save these two bars for breakaway" by default. There should be some risk/reward in going for the kill with your super vs. saving that meter for defense. I don't want to rip off SF too much, but one thing I've always admired is how useful each option they provide you feels.
Meter should go back to a more traditional format. Classic 3 bar meter works for me. Having three major things tied to your meter, really makes your decision making important, choosing between your super, your ex moves and breakaway.
Breakaway should be nerfed of course, forcing a delayed wake-up and letting the aggressor maintain some sort of oki game or try for some mix. Have more launchers in strings or normals, maybe bring back the nj. p launchers? I want more combo routes than we had in 11.