I understand the OPs sentiments. I was pretty frustrated with this mission as well. At first, I thought it was just ridiculously hard. Ends up there were supposed to be 8 other people in there with us but it was always one dude with henchmen who seemed to disappear at some point.
Ends up you just need ONE good group to get it done. Last night, a guild group was able to do the mission when the other team was entirely henchmen. We had a barrage ranger, an AOE nuker, a wells/MM necro and 2 human monks plus a few others.
The mission is very doable, even with the other team hurting you in the process. And I have to say I just LOVE the concept behind the mission. I really enjoy the way they integrated the incoming Prophecies players into the story. Just great.