From a World of Warcraft Developer who wrote a very successful book called The WoW Diary. (The book was kickstarted for over $600,000 and is still available on Amazon --for about $80 
Too rich for my blood, but I would love to read it. )
I would like to point HG to this excerpt:
“Game designers should build from solid moment-to-moment gameplay,” he (Staat, author of The WoW Diary) writes, “discovering where it leads them, instead of working backwards and forcing a vision to happen. The wrong approach is starting with a cool concept, and shoehorning it into the game.” *
*Bold italics mine.
For me this is the core of the frustration I feel around the game. “Shoehorning in cool concepts”.
If anyone is feeling rich, maybe they could send Sean a copy.