Remember that a large portion of people playing wow have not, and will not read the books. Not because they detest reading or shake at the thought of owning a Wow themed book, but because they would rather Bliz show the info presented in the book in the game itself.

For the longest time me and some of my friends theorized that Malfurion would be the end boss of the possible Emerald Dream expo. Essentially he helps you defeat said Nightmare, and then in turn becomes corrupted. But with the advent of the book Stormrage, and then the Cata expo those dreams were shattered. We started playing a game with Malfurion in it, but we had no clue as to why or how since us, as players, were not involved in any way shape or form in those events.

Many players want to be part of the BAness of our leaders, or at least witness the epic/traumatic events because we want a game that is not filled with holes instead of right now where we essentially have to notes saying, "In order to know why this happened please go check reference book X section Y lines Z.