It's not going to top WoW. Nothing will top WoW until Blizzard's next MMO. That's not to say GW2 isn't as good or better than WoW, it's just not gonna attaract that kind of fan base. One of the main reasons WoW has 12 million subscribers is because every PC on the planet can run it. I bet there aren't 12 million PCs in the entire world that can run GW2 at high graphic settings. The other challenge new MMOs entering the market have to face is that players now expect the kind of polish and depth that WoW has. How can any game, no matter how good the developer is, be as polished upon release as WoW is after 6 years of development and tweaking? Not gonna happen. Then add in the fact that it's very hard to pry WoW players away from that game because of how addictive it is and because of the relationships that the players have established on their servers. People don't want to leave a guild with 20 of their friends in it to go play a new game alone.

Having said all that, I definitely want to grab GW2 and give it a shot because it looks amazing and fresh =)

I'm playing Guild Wars and I'm completely lost. After having played WoW for some months, every MMORPG I played was about the same and I felt tired after few days...I bough the complete collection of GW after discovering how GW2 looks to be. And I must say that it's really different from other MMOs! Actually this is also a minus, I went through tutorial thinking that it'd be easy to understand the game, but now I had to stop a PG (and trust me, there are few players on Italian servers...) to ask how in hell I could complete quests without dieng, founding out that there are NPGs you can invite to your party!

So, from my experience, I must say that innovation can also be critical for someone not much into that kind of games...but it's also the main reason I chose the game for! So, if GW2 is innovative and they're able to teach the game even to not-usual-MMO-players I just hope that it becomes the most successful MMO out of there!