The argent tourney: Releasing an entire raid with limited original graphical assets was a poor plan after Ulduar; and all those dailies were ominous.
Mastery and forced final tier speccing: These two thing at the beginning of Cataclysm encourage me to wait and see rather than resub. They over limited player diversity.
The Cash shop: As a potentially returning player, seeing things I would pursue in game only attainable through real cash set a final objective that didn't require playing.
Cataclysm seemed fun, but by the time I had time to play it LFR was introduced. I saw the last bit of Cata story on a week of free time. Story and art assets are my carrot, and I got the carrot.
Pandaria didn't appeal to me, and dailies were so much a part of the process that I was sick of them during beta testing. Also, very few, very short five man dungeons didn't work out. Then there's the Pandaria story of fighting against the physical manifestation of bad feelings which reminded me of Carebears a bit too much. The talent trees of course are the expected result of the mastery and forced speccing from pre-cataclysm. I could really harp on Pandaria for awhile, but to be fair it had to be pretty amazing to draw me back at this point.