Hello Wreckfest
I think currently the 'Hybrid' classes are dominant (Classes that can both heal and dps)
Here is my PERSONAL opinion on the tiers
S Tier: Disc Priest
A Tier: Resto Shaman, Boomkin Druid, Fury Warriors, MW Monks
B Tier: Rogue (Mainly outlaw), Spriest, Feral Druid, Holy and ret...