A Japanese fact sheet has cropped up on the net and it boasts quite a bit of "information" on the largely mysterious Super Smash Bros. game for the Wii U and 3DS. It even pins a name on the title: Super Smash Bros. Universe, with the U in Universe stylized similarly to the U in Wii U, as you can see from the above image. It is likely that this fact sheet is fake, and that seems to be what most who see it are leaning towards believing.
If we are to believe it though, then we know that they will remove tripping and falling from the game-play, include more third party characters ala Sonic and Snake, and rebalance Samus to be more similar to her portrayal in Other M. The last official word on the Wii U SSB title was that development had hardly even begun on it (the team is/was largely preoccupied by the development of Kid Icarus) , which makes it seem possible that the document is legit because it barely contains anything outside of the title.
This neatly fits into the rumor category for now. If it is legit, perhaps it'll make Nintendo say something about the game to quell rabid fans. Knowing Nintendo though, it's wishful thinking.