I wrote a list of characters that should be in the next Smash Bros. Game. The "clones", such as Falco and Young Link and Luigi, will be given their own complete set of moves, NOT copied from the origional characters.
Mario
Luigi
Peach
Daisy
Toadsworth
Wario
Waluigi
Bowser
Bowser Jr.
Yoshi
Birdo
King Boo
Dr. Mario
Link (In Soul Calibur II's game form)
Dark Link
Young Link (In "Wind Waker's game form)
Zelda/Sheik
Ganondorf
Skull Kid
Ruto
Kaepora Gaebora (That annoying owl from Ocarina)
Koume & Kotake (Team fighting style similar to the Ice Climbers)
The Ice Climbers
Donkey Kong
Diddy Kong
King K. Rool
Kirby
Meta Knight
King Dedede
Samus
Ridley
Joanna Dark
Banjo and Kazooie (Team)
Grunty
Captain Falcon
Dr. Stewart
Samurai Gorah
Jody Summer
Kid Icarus
Viewtiful Joe
Captain Blue
Sylvia
Sonic
Tails
Knuckles
Cream and Cheese (Team)
Amy
Shadow
Rouge
Eggman
Captain Olimar
Fox
Falco
Prince Tricky
Krystal
Pikachu
Mewtwo
Jigglypuff
Pichu
Mew
Meowth
Roy
Marth
Ness
Jeff
Poo
Paula
Starman
Love Giant
Hate Giant
Mr. Game And Watch
Well, I think that's about it. I'm sure there are more, though. Wow, that's like 70 characters...
A new addition to the game would be creating your own character. You would first construct him from one of those wire-frame guys. Then you add clothes and stuff, and you can also design your own... uh, designs, on his/her clothes. And you can make their moves. It'd be cool. Two new items would be F.L.U.D.D. and the Poltergust 3000. In this game, I would always play as my character, Meta Knight, Ness, or Viewtiful Joe. This game definitly wouldn't be for GameCube. There's too much stuff in here. You'd have to wait for a new system to come out.