Today, Jo Bildo touched on the very reason why Warhammer is so compelling when many recent MMOs have not been as successful. And the reason is: WAR.
That's also why I like the game. From the moment you log in, to any area, you hear the pounding of cannons, and see the (NPC) enemy battling it out. The NPCs taunt you with the power of the Raven Host and other hated enemies. And if you tire of fighting NPCs, you can immediately jump into the fray by joining an RVR scenario if you feel like it, from the very beginning.
In WOW, well, the first thing I saw were wolves and rats and the usual backstory about someone dropping their wallet. Then you fight some bandits, but those aren't "THE" enemy, just "an" enemy. Then you go fight Murloks with their annoying noises. Because someone else dropped their wallet over there. And so on and so on. Forever, I'm fetching wallets for random people from random places, and it was rare that I ever saw a Horde (in the newbie areas) because few ventured so deep. By the time I did encounter one, I forgot why I cared, if I ever did.
In EverQuest II, we were promised a cold war between the two cities. A couple false starts when the game first came out let us sabotage the enemy, but without a compelling reason to bother, most of us just gave up and started adventuring side by side with them instead.
But in Warhammer, war is the backbone of the story from the very beginning; each racial conflict is the driving force of the whole game. Sure, you're still running 10 places and clicking on 10 things, but its FOR THE WAR. And that really makes all the difference.