The no flying debacle
The way they handled the warlords. Especially Kargath left a sour taste in my mouth and made me ever so salty.
It feels as if though they made WoD to cater to the crowd going "Uh Pandas are for kids" during the AMAZING expansion that was MoP.
Other than that? This expansion has left me tons of scope and time to level characters, earn gold and collect transmogs from raids that couldn't be easily soloed before the stat squish. Raids have been solid as well and the new character models were sorely needed.