WoW has lore for 10+ expansions. The universe is big, rich and has tons of interesting things to explore. I don't think that the lack of imagination is a reason to produce expansions slower. You really think there are months wasted with Blizzard guys sitting at a brainstorm meeting all saying "Sorry, I got nothing? Paul?" "No clue... Space... Hamster... expansion?" "Get real... we need to... uh.... phew that is hard!"