Red Mage.
Easy to pick up, easy to master, easy to execute, does respectable damage, slots in the best meta comp, highly desirable due to the physical dps raid buff.
It's not punishing at all, either, so if you die or mess up your rotation, you can recover instantly.
You also get great hats, you can rez healers if they both die (and I've done this so many times, it feels so good to be clutch),
You get rapiers and a beautiful battle stance. Corps-a-corps and Displacement have beautiful animations.

EDIT: Let me again mention the hats. Bard no longer has a monopoly on cool hats. Hats are very important for gameplay, I find, and Red Mage's hats are easily S tier.