Warhammer Online is shutting down in December. I played it for a bit when it first came out, and actually wrote a fair bit about it on this site.
WAR had several good ideas, most notably Public Quests. Having both an offensive and defensive target is one of my favorite UI innovations. I think that WAR has been quite influential on the design of the MMOs that came after it.
But ultimately WAR was a failure. I think it was a failure because, while it reached for new heights, it didn't get the basics correct. Chat was a nightmare, and the latency and performance were pretty bad. And who can forget the contribution bug. Not to mention that just logging into the game meant wading through a morass of splash screens and opening movies.
The real lesson of Warhammer Online is that cool design will generate hype. But polish and performance, the basic grunt work, are vital to success.