Tell that to SF3. Capcom alienated a lot of players by making Ryu and Ken the only returning characters (hell, they were originally not gonna put them in). People endlessly complained about the new characters. I'd say that if Capcom would make another SF (unlikely, unless it's a rehash) then they should put old and new characters in.
Well i dunno about here, but i do know that Garou Mark of the Wolves was pretty popular with some people although very poorly advertised here. It was very similar to SF:3S imo and only had Terry as a returning character. I guess to me, it was alot better because the story fit in better making Rock a much more attractive character(not just in similar moves, because there is enough difference to give him uniqueness). SF really needs a more consistant storyline.

They will surely consider it and the Street Fighter games are still played widely at tournaments across the world (specifically, Marvel vs Capcom 2, Street Figher 3: Third Strike and Capcom vs SNK 2). There is still a demand for it.
To me, its old games that people still play because theres none better out there. Marvel is really old, and as much as i love CvS2 and 3S, its a bit old too. Its just if you play fighters, this is most widely played overall everywhere, doesnt mean they dont need new games its just there hasnt been any better.

Theres no excuse for CFE to me, they should still have thought it a bit out. Its sorta like SvC Chaos to me, it could have been great, but it doesnt excuse its lameness now. As for SFA, its still rooting from older games, its not really a new installment, so to me its really more of the same with some extra fireworks. Same with SFAniversary, its a great game but its still not a new installment, as much as i love their new Hyper Fighting(even if its not arcade perfect i heard).