MoP was the final straw to make me say I am done with the game. The overload of repetition soon as you hit lv cap is absurd. I miss hard heroics like back in BC and when rep was hard to get but once u got it all you had to do was buy the items with gold. The game still has bad balance issues but we got pokemon? 3 man zerg dungeons? Extra tokens for a .00005%(made up % obv) chance to get extra loot from a boss? All this is considered good design? They keep pushing features that make people un social in a social game.
IMO it started with achievements. Their way of saying "no you haven't beaten the game yet". They have gotten extremely lazy after ICC raid Cata was a lot worse than MoP imo. MoP did bring some features that are cool i guess but there is a lot of other things that years in the unmaking still need to be fixed. Blizz will be their own downfall. I mean come on they actually think D3 on console was a good move.
My biggest gripe though would be just the whole panda thing and their lore. I don't like it at all. LK was so rich and deep. I read a lot of science fiction by R.A. Salvatore and the whole asian culture kung fu panda has not sit well with me. I haven't totally given up on blizz they have been in the game long enough to make some fun encounters at least. I look forward to their next xpac announcement. Till then there are some other great games coming out this year are worth the time to try.