Just finished this quest. It seriously needs to either be made a solo instance or have the respawn rate massively upped. I'd probably go with solo instance as it would be easier to balance, at the moment you will spend about 20 mins running in circles looking for things to control or kill because of low mob density and tons of players trying to complete it.
If you haven't played this dungeon you could feel that way. However if you've played this dungeon compared to the rest of the public dungeons, you'll realize this one is far different than the rest. The way this one is set up leads you to running in circles with literally nothing to do for most of the time. Other dungeons are busy with lots of killing etc, but the objectives don't have you killing or interacting with the same low density mobs for two checkpoints in a row. This one is really poorly designed and a cut below the rest.