I despise the thought of the game being mainly world dungeons. It's a horrible mechanic because it breeds rude players and limits the access of content to a small percentage of players.
I'm not against world dungeons, I enjoy those as well, to an extent. But I have played many MMO's where my group will fight to the boss only to find out he's been taged, so we wait for a respawn only to have 4 other groups waiting to tag a the same boss. If we happen to get it, often times other players will try and train mobs on us to get us killed so they can claim the boss. Sometimes they fail, sometimes they are able to bring enough mobs where our healers get rushed with adds and the group ends up wiping.
These tactics are cheap, and annoying. It comes to the point where if you wan't to get that kill, you have to be rude back to people, and try and get them killed so you can claim a boss. Overall this type of game play creates more aggression between groups of people instead of having a community where players are respectful and helpful.