http://www.tale-ffxiv.com/boards/top...-e3-interview/
When was the decision made to add a class before the expansion?
We do have plans to release new jobs and new classes at the expansion; it wasn't like we took a job and class from that expansion and decided to release it early. We've always planned to release a new class and new job at a patch.
We've always thought that we needed a scout or a technical type of class. It's one thing that we didn't have in FFXIV and we wanted it, especially with the release of the large scale PvP. We wanted a class or a job that could do the scouting and stealth type of actions, so it was just natural to bring in that type of class to coincide with PvP and that type of content. The fact that the players have been begging for a thief-type class or a ninja-type class for a long time, we're happy that we can bring that to the fans ahead of the time that they expected.