Thanks Rosti for the awesome banner!
Figured I'm not the only one who wants to start speculating so let's discuss everything from roster choices to gameplay! Heated arguments are more than welcome.
What we know so far:
The next Super Smash Bros. will be made for both 3DS and Wii U, with an emphasis on connectivity between the two versions. The portable version is said to be a more "personal" experience while the console one will be more "stadium-like."
It will be jointly developed by Project Sora and Namco Bandai Games. Key staff members include;
Masahiro Sakurai
Masaya Kobayashi (Ridge Racer, We Ski, Go Vacation)
Yoshito Higuchi (SoulCalibur, Tales of the Abyss, Tales of Vesperia)
Tetsuya Akatsuka (Mobile Suit Gundam: Extreme VS.)
Tekken's main development staff
and many more...
News:
Announcement of Sora X Namco collaboration
Iwata Asks: Super Smash Bros. (Via Andriasang)
"A change of direction might be needed in the next Smash Bros." - Sakurai
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As someone who played advanced 64 and Melee for a while, I'm obviously more concerned about the gameplay mechanics than who makes it in. Brawl had a phenomenal roster but the game was a snoozefest when played semi-seriously. Nintendo should honestly go back to what made Melee work and tweak the speed just a bit. Why Melee if Brawl was more successful? Because the former simply had the perfect balance of fun for the casuals with enough depth for the hardcore, and that ties into Nintendo's desire of making the Wii U a platform that satisfies both demographics.
Roster-wise, the Nintendo side of things has been covered pretty extensively. There's just a handful of characters that can be added before we delve into Waluigi territory (i.e. shit nobody cares about). More 3rd party additions is where it's at.