To address the desire to become "the next WoW": sure, WoW sales would be great for ArenaNet. However, that's not their immediate goal — sure, in time, they would love to build a player base that could compare to WoW's, but I think we'd all be a lot better off if fans for both GW2 and SW:TOR stopped talking about WoW killing. WoW will die on its own at some point... it's not going to last forever. Whether Guild Wars 2 contributes to that or not, most of us are confident that it will draw a respectable amount of players to the game, whether they be full-on players or players that might play a subscription MMO on the side.
This is totally lame, but if you're at all paying attention to primetime TV right now, it's like "The X Factor" vs. "American Idol" comparisons. I'll probably get laughed at for referencing these shows, but hey, the comparisons work. Don't expect an out of the gate hit like Simon Cowell did!