Great mod! The goofy antenna hair looks better than I expected.
I'll say that there's no pretty extensive support for "Metahuman" as the class here -
Meta Liberation Army and
Meta Liberation War with "Meta Ability" being a synonym for "Quirk" in-universe. But the temptation to make it give the universe their own species, and "Quirkhuman" is a fair approximation of "Metahuman."
I don't mind him being more of a general-use hero because, in-universe, he is; we see All-Might from the perspective of students, so he seems student-centric, but he's really a huge global presence. Definitely a JLA member in any crossover. Light touch of an +1 Defense for students works. I can imagine some of the kids (Deku and Bakugo) working off of Champions in some way.
GBPU is awesome, and I can imagine there being some rule wonkiness with that extra turn placement but I hope it works without issue. Big, splashy, but simple power for a big, splashy, simple guy.
Only real knock is that knockback feels a little bland for him in comparison. I get that he's smashy-smashy but, I dunno, could use a bit more oomph? Can't think of what, exactly.
Also, even if he can't fly, he's definitely one of those "jumps super far and it may as well be flying," so I dunno, we might want to rep that here too?