Neither of the two classes I play heavily are OP in PvE, which is primarily what I do with them.
I'm happy enough that frost mages are competitive in PVE. I'm thinking about pulling my old mage off the shelf and level it up from 80 to use it again. My spriest is fine but I don't think it's OP for PVE. I understand that it's been quite good in PVP though.
The key to the secret code words is this: "We're in a good place right now" = OP mostly.
A bit of civility and respect for others opinions goes a long way toward getting any respect in return. Overly hostile, profane and insulting posts are a sign that people don't really have anything to say. Profanity is best served out in very small doses.
"Forum drama exists because people enjoy creating it." - ML/2013
My UH/Blood DK definitely feels overpowered. He seems to have a greater capacity to easily, instantly renew diseases compared with my other classes that makes me wonder why their duration is so long. Self-heals are also pretty crazy, which I guess is good for soloing bosses.
On my Destro Warlock, I don't feel so OP. I like the way the ember resource system can make you very effective against large groups in PvP (faster ember generation from Rain of Fire hitting more targets). I think the tears about Chaos Bolt are a little uninformed.
Enh Shaman, so long as I have Well Fed, various Alch potion buffs, can feel very satisfying but not OP. PvP seems more thrilling with this character, unless I keep running into more than one player.
Resto Shaman - well, I can put out some pretty awesome heals in PvP despite having pretty crap gear for this guy. Fewer instant-casts make him feel less OP than, say, a Holy Paladin or Resto Druid.
Arcane Mage is good fun, but definitely not OP in PvP.