I think most of it had to do with the national storyline quests that were listed under "Quests" and not "Missions" that got people confused and made them quit doing it because they eventually just forgot where they were.

Not to mention people didn't know you could do any national storyline quests regardless of who you were allied with. Lots of people still don't know that.

Which is too bad, because WotG is probably the best expansion they've released in terms of story.