Wrong there Slig, very wrong, first of all, in guildwars you can interact with everyone, as long as your in public places, such as towns, outposts, missions, once you created a party, you can also talk in 'party only'
All
Guild
Party
Whisper
So that pretty much means you can talk with everyone you want

Once you left the outposts/missions/towns and move in the battlefield, you get a 'own' world where no others are except you and your party.
And next: WoW has 5.5 million subcribers, people are going to boycot WoW know why? there paying to play the game for over 2 years, and all of a sudden they have to pay for the expansion aswell. Which means they lose customers, GuildWars brings a expansion every 60 months which costs 45 euro's, Arenanet is pwning WoW in the long term this way.
/teh Neo
EDIT: Lack of character customation?
There are 20 armors for each characters, all different price classes, from 1.5k armors to 500k armors (per piece)
Also, you can dye your armor pieces ALL colours you want, you can mix your own dyes which makes you unique, and the character faces and body's have enough customation.
There are 140 armors, and when factions comes out, there are 280 different armors pieces, and 8 more new dyes, which means there are 16 different dyes... You can mix all and get all sorts of colours, your character can be more then unique.