“So, do you remember that KOS-MOS and T-elos, from Xenosaga, were in the first Project X Zone game? We didn’t include them just because Monolith Soft was developing Project X Zone, we put them in there because there were so many fans of their games on the team, and that they happened to make sense for the world of the game.
“The reason there’s not Baten Kaitos characters in the story is because they just didn’t seem to fit in anywhere. As for [Baten Kaitos] itself outside of Project X Zone, well, I can’t really say much about that yet, but I think we need some substantial feedback from fans before moving forward with a project like that. What do they want to see from it? What platform do they want to see it on? If we can gather more voices for Baten Kaitos, then maybe we can start something with Bandai Namco Entertainment. That’s about all I can say right now!”
Read more at http://www.siliconera.com/2015/07/14/want-more-baten-kaitos-games-let-bandai-namco-know/#45AVfXPA17KRW3pL.99
Ok, this was surprising, let's hope we get a new game someday, or at least some BK characters in Project X-Zone.