Ive been beta testing the game for a VERY long time now, i'm an elder beta tester from closed beta, and i will tell you this now.
WAR WILL, kill WoW. Its not going to be immediate. but there are a few things that definitely blow the shit outa wow.
For example the world pvp, there is pvp in every single zone in the game (little "lakes" if you will) where if you enter, you will be killed most likely. this game is built around pvp, and it does an extremely good job at it. At one given time or another depending on how everything is going, if you make it to the battle cities where each faction is trying to win over the town, you will have massive battles of 100 on 100 or more and its just massive waves of people rushing at you. And there is no running through people bullshit. if both people are flagged for RvR (pvp) then they cannot go through each other. So basically, if you need to stop the enemy from advancing, you can quite literally form a wall of people and force your enemy to fight through you if they wanna get to the other side.
Another aspect is the public quest system. honestly i absolutely love this, there are sometimes multiple public quests per zone, and as many people who want to participate are able to. Its basically mini raids with random people. and in the completion of the quest, the participation and contribution amount are calculated and you have a chance to win a loot bag, which ive won some that contain epic quality items.
Then overall, their scenarios (battle grounds) are amazing also, very well thought out and very fun. there are many different types, so youll just have to play to see them all.
Overall, this game is either going to kill WoW, or it will atleast take a large chunk of people out of its population
If your a PvPer then this is your game.
ill post my server when we go live