It's just speculation on my part.  Sakurai mentioned that he didn't want "duplicate moves" in this game back on the old Smash Bros. Dojo website.  He also said that cloned moves were only included due to time limitations on Melee.  Brawl suffers no such time limitations, and since he said he doesn't want them I would assume cloned moves, like Falco's and Ganondorf's movesets, are gone.  The reason I think Dr. Mario, Pichu, and Y. Link are gone is because the very nature of those characters demands that they have cloned movesets.  Roy is gone because he has been replaced by Ike as the new "most recent" Fire Emblem hero. 

Falco should be returning due to his popularity.  He will need different (non-clone) moves though.  Ganondorf will be returning because he is the Zelda staple villain.  He's most likely going to be a sword fighter in this game instead of a physical fighter.  He was meant to be in the last game, as evidenced by the sword he pulls out when he wins.  Again though time constraints limited development on him.

thanks for the information! im very glad to know falco should be back.
what do you think about charactors like these entering the game
Waluigi Jigglypuff Luigi Mewtwo Game&Watch

Waluigi no.  Mario series won't be getting any new characters other than Wario.

Jigglypuff is an original SSB character.  I can't see them ever removing an original character.

Luigi see Jigglypuff.

Mewtwo is probably returning.  Can't say for sure, but I would expect him back.

Game & Watch.  Same as Mewtwo.  I can't say for sure, but I would expect him back. 

Remember that they aren't going to announce every character on the site.  I'm sure many characters will still be hidden come December when the game is released.   

thanks to other folks out there for the captain olimar support. Hope it comes to pass!

i know its weird to say it in this thread but i dont want to create a new one, but is there a Marios Strikers thread?

I'm guessing Sonic will be the only other 3rd party character.  Mega Man would be cool and all but I think that's just too much licensing stuff for Nintendo to go through. 

awww

I'm really not even too sure about Sonic.

Mega-Man would be cool, because he's easily the third-party character most associated with Nintendo.

Pac-Man + Sonic would be cool, because those 2 along with Mario, DK, Pikachu, Link and Snake makes arguably the 7 greatest characters in videogame history.

But Sonic is the most likely by far because of the Mario & Sonic deal. We know that Nintendo is providing the biggest IP, and SEGA is doing the development, and SEGA has publishing rights outside Japan. Maybe Nintendo is covering the marketing, and then SEGA is providing Sonic for Smash. Hopefully it's all part of the same elaborate deal.

My estimation for Sonic is about a 75% chance. Good, but not for certain. I'd love to have Mega Man (don't really care for the idea of Pac Man much), but I don't think his chances are good.

Sonic would be great IMO. sales might be higher if he's in maybe, I don't know.