I honestly wouldn't care. Infact, I'd enjoy it. Smash Bros did this type of gameplay almost flawlessly. And I feel like if All-Stars tries to mess with it too much it'll per robably not be as fun oir too slow and no one will be happy with it. So Why not be just like Smash Bros? They're already ripping off the concept enough so may aswell take the same gameplay mechanics.
It'd pretty much be Smash Bros with a brand new roster of more serious characters. Which I openly accept.
I know some people really want them to be "Original" but We've already gone passed the point of original. Its just my opinion though. No bashing please :)