I agree with the premise of the thread. A healthy MMO appeals to a broad variety of players and personal tastes as opposed to a select few. I am very much a casual player but casual does not equal wanting to see the game stripped of any and all difficulty and depth. I'd like to see more content with staying power that is geared towards midcore and hardcore players.

Eureka and Bozja fulfilled that niche for me. Perhaps Crystalline Conflict could have if I were able to queue up for it with my partner - but that isn't an option, unfortunately.