I don't follow. Just because Sakurai is talking means that Geno's Mii Costume is less likely? Can you please explain a little, I'm quite confused?
So in short, if Sakurai presents, expect something. If not, expect Geno costume returning. Hopefully that answers the question.
EDIT: Think of it this way. It is an odd situation no matter how you look at it. Sakurai went out of his way to make a big deal that Geno's Mii Costume was a thing. Now we have an instance where we do not know the fate of our Star Boy. Is he coming back as a costume? Is he more than that? Or is it nothing? With how big a deal it was in Sm4sh, will it be glossed over? I think Sakurai is the person to address it. Whether through The Hero's video, or a famitsu column stating why he is a costume again even though it was a big deal last game.