Some more of the Phantasy Star cast obviously. Rolf would work great, maybe a character with slashers too.. Alys or Kara (PS3) anyone?
Rent-A-Hero would have to make another appearance.
NiGHTs.
Metal Sonic
A Pro American Trucker for filler
Some of the Fighting Vipers characters.
Virtua Cop (Like Janet from FMM)
Maybe a character built from Sega Consoles. A Master stsyem as the core, dual dreamcasts as shoulder clades, gamegear arms. His special moves could involve controllers, 32X's. The sound effects would range from the bleeps and blops of master system, to the clear sounding stereo of the dreamcast depending on what body part he attacked with.
Dont forget, he would be wearing those master system 3-D glasses and have the master GUN in a holdster to his side.
Virtua On Virtuoids for sure! Well miniature versions of the giant mechs.
Lundi and Lagi from Panzer Dragoon. Or just the Blue dragon
Sega would be able to put together their own fighter and forget Capcom all together.
I personally thing that a 3D fighter in the style of Fighters Megamix (but undergoing the necessary upgrades of course) would be excellent. Over exaggerrated attacks that send an opponent flying in to a wall or 30 feet in to the air.
The armor existant in Fighters Megamix would have to come back too, I think. And the ability to send an opponent through a brick wall!!
Oh man, I shouldnt talk about it anymore. I bet I'll freak when I remember that its not real