Parts of it were great. I liked the silly Mylune quests in Hyjal, and the random NPCs in Setheria's Roost. I quite enjojed peak-hopping via spider's webs. But the whole Druids of the Talon area is just damn painful (I've only once got through the intro escort without dying on the way), and the much-vaunted random quest mechanism just didn't have enough variety in it. I made a big mistake by opening that up before the Shadow Wardens stuff, which was much more fun.
In the end, there was far too many "kill x of y" and not enough interested and innovative mechanics. The "rune dash" area and "bird collection" quests were the only ones that struck me as noticably new in feel and tone.
I admired the concept, and struggled through the execution.