Not content to be outdone by Shigeru "we might have some more Galaxy one day, who knows?" Miyamoto, Smash Bros. director Masahiro Sakurai used his Miiverse pic of the day to give us a little more than vague hint - Galaxy's made the HD transition in the form of a new stage.
Not only is it a spherical space for fictional punching but, as Sakurai explained, it uses Galaxy's unique take on gravity to change how the game plays out: "A new stage, Mario Galaxy!! The pull of gravity emanates from the center of the planet, so this will require using brand-new tactics."
He followed that up with a second screenshot, which describes "what happens when you stand by the edges. Vertical jumps and getting hit upward will shoot you up diagonally."
Is it too much to hope that smashing someone into space leads to a Gravity-esque interlude, where Mario goes all Sandra Bullock?