Game Informer have conducted a post release interview with Final Fantasy XIII's producer Yoshinori Kitase. In the interview, Kitase was questioned about about the development of Crystal Tools and when asked what he would change, he said they should have concentrated on improving existing technology rather than creating an entirely new engine.

"Tools and engines improve through a process of trial and error and countless revisions, and that’s what really makes them more efficient."

Kitase was also questioned about the rest of the Fabula Nova Crystallis compilation. When asked whether there are more games in the compilation planning to be announced he answered "Please look forward to future announcements." Even though we've had evidence to believe this before, that pretty much confirms it.

Source: Game Informer