WoW endgame is about raiding. Sure you can PVP, but considering Blizzard doesn't put as much effort into it (actually adding new content, not "balancing") you can't really say that it's a main selling point. Most of everything else is just busy work like Achievements.
WoW did one thing right. They made an addicting game that people just can't quit for whatever reason. For example: they don't want to let go of that one character that has all the cool achievements and mounts. Attachment is hard to break in any circumstance, which Blizzards marketing team is amazing at exploiting it.
Is WoW a great game? Yes. Is it a great MMO? No.