In or truefulness I don't really care for 3rd parties. Sure, Sonic was a nice treat. . . but his games f***en suck (past the 2D times) and sega is running his name into the dirt (I really believe sega should just become 2nd party to Nintendo so that they could make atleast one home-run-hit 3D Sonic game with Nintendo's help. . .Brawl Sonic has more of a Sonic feel than Sonic in his newest games) and Japan is REALLY making it clear that they don't like sonic games any more with SonicRA selling 1,500 in it opening day.
Megaman. . . the only Megaman worth having in Brawl is the classic Megaman and I don't foresee him being in any new games. On one hand I feel that the newer MM would give the devs full range to go completely nuts with and make some off the wall type attacks but, on another hand, for some reason the series is soo. . . less than it use to be that the first MM is the only one that seems likely. I over all see Classic MegaMan as boring but thats the only one I think has any liekly hood of being in so I hope he turns out fun.
If there are any more 3rd parties I surly hope they are some WTF characters like Snake was. I want a 3rd arty character thats a corrent huge character with games that are not shells of their former glory. I want something like. . .Sora from KH. Appearing in brawl would be the cherry on top of the rumors and rumors and RUMORS (soo many rumors saying this) about a KH Wii title and this is a series that could greatly help Nintendo if they become closer to it.
Or maybe even that FFCC:Wii main character guy. He would be interesting (Wind powers). NightM from SC would be great. . . even Lloyd from ToS would be exciting. Hell, anything from a corrently big series that comes in with a cool, flashy move-set would be to my liking at this point.
Simply put, I really have no idle who else would get in after MM but I hope it's a newer, cooler, corrent character and not just some old lame like Pac-man/ Bomberman/ Ray Man or any other {insert Man here}.