An open world dungeon would be a joke. The place would get zerged until everyone had had everything of value from it. The only way to avoid that would be to implement something to stop larger groups of players from going in all at once, but at that point why not just make the thing an instance?

Quote Originally Posted by BreyVoreas93 View Post
I would love to see the terrain be dangerous, falling rocks, quick sand, weather
What would this add to the game beyond an area that players would have to avoid? Open world MMO zones have to be designed with the idea that players will be going through them many many times. Traps like that are fine in a linear single player game where the player will see them once and then never go back there again, but in an mmo, players will figure out the fastest, easiest way through the zone, and then ignore all of the terrain traps. Why bother wasting resources designing systems that players are going to ignore? It's worth mentioning again, MMO players will always find the fastest, easiest way to do anything.