I dunno, I agree with Mako. I understand what Masa is saying and agree about the whole milking part, but when it comes to fighting game series mechanics, it only makes sense to add new characters while keeping the original ones. Sure, a lot of us are tired of seeing Cloud/Sephiroth, but that would just have to be a necessary evil in the case of a Dissidia 2.
I mean, they just can't exclude those two from a fighting game because they're milking them to death (which, they are), that would almost (not quite the same, but almost) like leaving Ryu out of Street Fighter, Paul out of Tekken, etc. They sort of have to be there and we'd just have to suck it up.
And as far as fighting games and stories, well, King of Fighters has an ongoing, overarching plot that rivals FF.