KI is kind of an incomplete game for starters. Presumably it will have some sort of persistent user base as more content is added, but I'm not sure this is the way to handle the equivalent of episodic content.
On the plus side, the one player demo will always be there for new XOne owners, so presumably the game should pick up at least some new players.
As it's been said, the fighting game genre has become a much smaller, concentrated niche than it was in its heyday, so there may have been a bit of artificial enthusiasm from Xbox fans with regards to the level of demand.
I would have to say that players who were fans of the original KI way back on the SNES would probably be the core user base and that nostalgia may not necessarily be the strongest thing to bring players back to a genre most have probably moved on from.







