Every single dungeon/cave I've gone in so far (up to level 20) has had the same problem of way too many people in them. All I have to do is basically walk to the end without defeating any enemies and then I get to see the boss, who seems like it would be fun to try and kill but is now dead and has about 10 players standing around him who are all waiting for him to spawn for the 30th time. The dungeons/caves/whatever definitely need to be instanced. Maybe the public dungeons don't need to be because they aren't really part of any story line. But any quest cave or dungeon has to be.