GW2 sounds fantastic. The only issue it might have is how many people can actually run the game. WoW has 13 million players because just about everyone on Earth can run it at a steady 30 fps or better. GW2 will be lucky to have 3-5 million people world wide that can actually run it at it's full potential. Probably not even that. People don't generally like buying a great looking game then having to turn all of the video settings down to low just to play it at 20 fps.
With any luck the devs have crunched the code well enough that people won't need to spend $500 on PC upgrades to play it.