Hello. Im an employee at Nintendo of America. I cant say much more about my specific position. But I can tell you this.
There will be a Super Smash Bros. Direct later this month. It will be approximately 45 minutes long, the first 25 of which will be a huge exposition on the 3DS version, and the latter 20 minutes will largely be information about/hinting at things for the Wii U version. Heres as much info as I can recall.
1. The Direct is essentially made so that all of the Starting characters will be known before launch. Because of this, Wario, Ice Climbers, Falco, and Ness are all revealed to be returning. Wario is shown in a trailer at the beginning, which also introduces a newcomer: the Chorus Kids from Rhythm Heaven. Not all of the confirmed characters will be playable from the start, but I cant quite recall which characters will be unlockable. I do know he mentioned Sonic, Luigi, and Lucina. Snake is shown at the very end of the Direct in his own trailer.
2. Classic mode has gotten revamped and now has path selection, a more elaborate difficulty selection based on Kid Icarus Uprising, and its generally a lot more elaborate.
3. There was a little montage of Boss Characters on both versions. Yellow Devil is one of them, as is Petey Piranha (who appears to be fighting in the same stadium from Brawl, but is now without cages), Dark Pit on Palutenas Temple, and King K. Rool on a new Gangplank Galleon stage. Ridley is mysteriously absent as ever.
3. Theres a bunch of minigames which are based on classic Nintendo games, only on the 3DS version. Balloon Fight is a mode where four Villagers with infinite Up B fight on the Balloon Fight stage. Theres also a Punch-Out mode where a single player uses Wire Frame Little Mac to take down various foes from a perspective behind Mac in the Boxing Ring. I also noticed an Urban Champion mode, a Mario Bros. mode, an Ice Climber mode, and even a Pac-Man mode.
More to come.