Well, I mean, Superman's pretty small compared to Galactus... Like he's human size pretty much, I guess? Don't quote me on that, it's been a while.

Nah but in all seriousness I think as long as nobodies stupid about it, power scaling should be fine. I have no idea if we're fighting a big villain, I think we are, but you also have to realize that all the heroes will be fighting them at once. Power scaling should be resolved once we have a grasp on who the villain is.