Back from CATA, which Tank class should I main?

Hey, I re-up my subscription for WOW. I don't have much time to really waste as I work full time and go to school. I was wondering what Tank class should I main until I have more time later on. I haven't purchase legion BTW.

INFO: Draka Server, Horde. 85 Paladin, Hunter and Warlock. 60 DK and 32 Rogue.

Here are some wants for the class: I want a class that has a reliable DPS spec also for leveling and whenever I want to take a break from tanking. DPS spec that is good enough to raid. (eventually) Smooth Spell Rotations Looks Badass? Should I just get Demon Hunter and Purchase Legion?

Any advice on this subject would be greatly appreciated.