well I don't think there are gonna be clones of people this time. Luigi is replaced with Wario Ness is replaced with lucas Jiggly Puff replaced with pokemon trainer maybe but I think Falcon is too popular to be replaced.
more rumors of beta test channel
http://www.miiplaza.net/newsrss/1770677
http://www.qj.net/Rumor-Nintendo-releases-Brawl-Beta-Demo-Channel/pg/49/aid/110926
maybe Luigi, Jigglypuff, and Falcon have to be unlocked like in the first 2 or maybe replacement characters are being made for them like Lucas was a replacement for ness
I mean when your trying to play you don't want to have to pay attention to where the level is going and if the level is aways moving and small like pokefloat then you cant use moves like yoshi's egg roll
Maybe Ridley will be boss for the single player mode like petey piranha just a thought. DEDEDE with special waddle Dee throwing move that would make my life complete