Sadly, I have only one night of our worst performance to show. Horridon has been weeks of disappointment for us. We only raid 2x a week for 3 hours each, and this boss is killing us.
Last week, our best attempt got us through all 4 doors, wiping on horridon at 4%. This week we struggled to get through door 3 (and sometimes 1 and 2). Door 1 was fine once we got the replacement tank (the pally) to do the slow backup routine to keep the melee out of the sand. Door 2 was horrible anytime any of us missed an interrupt on the priests.
We've stopped using army on door 3 because of how it stopped the MDPS from getting involved due to badguy AOE spam on the army stack. I'm thinking we need to go back to using it. After army died a ton of adds were still up anyway, and the tank gave them the slow walk back to door 4, which caused a ton of frost bomb AOE in/around door 4. To resolve this I've asked the tank begin handling the door 3 adds on the area where horridon spawns between doors 2&3 to buy ourselves some kite space.
Door 4 (when we reach it, which has only been a couple of times) has been an absolute mob scene of too many adds to handle. I've read suggestions about army here, and we do have two armies to burn.
The two times we got to the post door phase our healers were OOMish (but we had healed through poison stacks there, which ate a lot of mana).
You'll probably suggest having a priest go shadow, but the one disc priest we have with shadow experience doesn't do much more DPS as shadow than in atonement, and I figure 2x disc atonement = 1 dps anyway.
What can you suggest?