Today during Square Enix's Final Fantasy XIV: A Realm Reborn livestream, director Yoshi-P revealed a new class and a new job -- the Rogue and the Ninja respectively. The rumor was that new classes would be coming out in a future expansion, but Yoshi-P revealed that it would be "sooner" -- like, Patch 2.4 soon.
The Rogue will turn into a Ninja at 30, effectively morphing the base class into the full-on job. The two roles will also play a heavy role in the lore of the game, and their story will be justified within the confines of the game.
As far as mechanics go, movement speed will be faster as a default, and you'll earn less fall damage than other classes. Poison blades and dual wielding is confirmed, and it is a straight DPS class. Healers and other support are being considered for the new expansion.
Yep, I'm totally leveling a Ninja the day it comes out.