The game is free to play which is automatically an invitation for trolls, ignorant people, retards and whatever you may want to call them. And there will be a lot of them!
Already seen many people in this forum who think they are so much better than any other person from other games, especially WoW of course! Funny thing, which does makes me giggle at times, is that they are in a little subforum on a huge WoW fansite.
Best community I have ever seen and still is, is the one from DAoC and I have seen many communities. But GW2 will most likely, just as any other game, have an ignore list, and I hope it will be endless.
The only thing that cuts the "bad" people down a little is that they cannot really ruin or steal to many things for and from others and you don't even have to group with them! So that's great!