Quote Originally Posted by Shiro--Tsubasa View Post
Not entirely true. IIRC Ninja was released mid expansion. Whose to say we won't be getting one mid expansion this time as well.
The devs themselves, pretty much. They've talked about how splitting part of the team to work on NIN introduced a lot of difficulties because they had to divert them from Heavensward, straining both the half-team that had to develop and balance a job mid-expansion, AND the team that had to do more work to make up for their loss on the Heavensward team.

It's kind of like the Sch/Smn split, it sounds like something they experimented with but aren't inclined to repeat.