I'll decide on how easy it will be to surpass depending on the amount of original Movesets that return
If Mewtwo isn't in; it'll be INCREDIBLY EASY to surpass. i.e. just add Mewtwo.
But this method of making Smash Bros games can't go on. Melee was supposed to have been made as if it was "the last" Smash Bros game, and they've taken the same approach with this one. Is it more likely to be true this time? You can't make EVERY game in the series like the was the last, otherwise you'd know that you would never really work all the time...
So this could be the last Smash Bros game, and if it isn't, it's more probably the last Smash Bros game Sakurai will work on.
Are Sora a part of Nintendo?