I think you’re overstating how hard learning new chars is in this game.
There are valid complaints about the game, but button scheme? It’s not complicated. I don’t see why not being SF-ish makes it worse.
I think I found your problem.
Marvel’s button layout is different but it’s far from complicated. You have attacks of increasing strength and a dedicated launcher in order, and mapped to your thumb, index, middle, and ring finger (at least on stick). Plus, you don’t even have to learn someone’s launcher input, they’re all just S. If anything this makes it way easier to learn characters than say, Marvel 2.