Apart from numerous re-releases and spin-offs, the Final Fantasy series isn't exactly known for its frequency.The most recent title, Final Fantasy XIII, was released in Japan in 2009 – four years into the lifespan of the current generation of consoles. Speaking to GameReactor, Final Fantasy producer Yoshinori Kitase expressed his belief that Square-Enix needs to speed up development times to keep the series successful.
Kitase pointed to annual western franchises like Assassin's Creed, Call of Duty and Battlefield, saying that the one to two year development cycle would be "the best way to keep [Final Fantasy] fans interested and attracted to the franchise." He elaborated that Square "learnt a lesson" from the long development of Final Fantasy XIII, and that subsequently, Final Fantasy XIII-2 has taken around one and a half years to complete.
It's worth pointing out that XIII-2 reuses many of XIII's assets and, indeed, some of its characters, which probably helped speed things up considerably. Of course, there are other ways to shorten development time ... opening a new studio, perhaps?