As someone playing since S08, class wise is the second best season I have played (S8 was the best IMO), people just cry too much.
Things you will find:
- Ferals, frost dks and ret pallies still have huge bursts.
- Warriors and BM hunters can put a load of pressure in very small intervals.
- Resto druids still heal for far too much with hots alone.
- Mages have absolutely insane amount of ccs now (prepare to hear "polly" a fucking lot when playing against one).
- Rogues are hit pretty hard, have loads of control (6s stuns... again and again and again) and tank a lot.
- Offensive dispel is still a HUGE part of the meta-game.
- Loads of pally healers spamming denounce.
- Everyone plays a alliance now and every DPS that can be human will be human.
- Monk life coccon CD is very, very low.
Playing on 2k ~ 2.1k MMR in the last weeks my view of the game:
Popular comps:
- God Comp (OMG, the pain! 15 minutes of non stop CC). Variations with pally healer were somewhat popular.
- Monk TSG (infinite pressure).
- RMD (same as god comp).
Semi popular comps:
Jungle Cleave, Thug cleave, KFC, smoke bomb cleave
Very rare comps that I still found:
LSD 2.0, PHP, WLS and RLS (or variations with other healers).
Most other comps were pretty rare for me (I found a double healer - dk / druid / priest - team once, but we are in year 2015, so I guess it is already ok to be gay). Still I think this season the only singular spec that is not viable is elemental shaman (not counting tanks for obvious reasons).
Finally, as for WW monks I did meet a few, monk + resto druid is very annoying to kill, but it dies eventually... I have seen a KFChi and a Monk / Shadow / Shaman once.