My strategy won't be for everyone but maybe one or two points might apply to your class. Here's what I've learned after running this scenario on (10) toons...
- Aggro as much as you can handle in the first wave to save your NPCs wear-n-tear (you need them looking good later).
- This a good time to burn a health pot, the cool-down should be up by the next wave.
- Try to save hard-hitting skills for the alert mobs that pop up (a spy, dragon, spellcaster, etc) They're much more resilient. There's a target over their heads...hunt them down
- The second wave is called Endure the Assault or something like that. Tanks may be the only class that can try aggroing the whole lot of them. I tried to get as many on my toons and always had to back off, singling out the ones that were climbing all over me.
- It gets ugly late in this phase; your dead npcs rise up against you, pesky low health mobs are everywhere and there is mayhem. My method was AOE a couple concentrated places, aggro one or two from long range and single out near deaths up close. I always stayed near the court and had to use a health pot at least once.
- The Primordial Horror is the boss in the final wave. He's not nearly as tough as the previous wave. In most cases, I had to blow most of my cool-downs before him. What I did save for him was my Call To Arms buff/spell. He dropped fairly quick.
My lowest toon was item lvl 500 destructo warlock lvl91 and he survived okay. As someone above stated, the reward was yawn but the fight was exciting; it felt like a mini-raid.
Please add your strategy comments or point out whatever I may have missed or got wrong and I'll try to edit it with Kudos.