I agree, it's doable. Here are some suggestions / clarifications that will make us kill him more quickly.

1. EVERYBODY needs to understand light phase. We're rocking about 85% understanding on about 90% of the mechanics. A single person who fails to understand the mechanics can easily wipe us on light phase. That means EVERYONE needs to know what to do. Here's how you manage light phase.

• If you are targetted with a blue or red beam: Don't panic. Get yourself relatively close to the boss and wait for the cones to spawn.
• If you are targetted with a blue beam: Ask in mumble if your current position is okay if you didn't see the blue spawn point. If it is okay, just stand there near the boss. Don't move.
• If you are targetted with a red beam: Listen to people call out where there is an add. Try to position yourself in a way that when the red cone spawns, it immediately reveals a red add. After the add dies, listen to people who are trying to give advice about what direction to run (if you didn't see the red add spawn points). While you run to reveal the next add, don't dawdle. Move quickly and run around the boss at a short radius from the boss, not a long one. Pay very careful attention to when the add spawns, when it does, stop running immediately. Repeat this process until all 3 red adds are dead.
• If you have difficulty knowing if you've been targetted by a beam: pick up weakauras prior to tonight. I have a module that I can export to you that will place a yellow, blue, or red exclaimation mark right next to your character if you've been targetted.
• If you're ranged dps and ARE NOT targetted with a blue or red beam: When the initial beams come out go to the yellow beam while you continue to dps the boss. When the yellow cone spawns, stay in that cone and follow it around the boss staying as close to the center of the room as possible. This will enable you to be in range of most red adds so you can help kill them. If there are no red adds, keep dpsing the boss.
• If you're melee dps and ARE NOT targetted with a blue or red beam: Get into the red cone. Stay in that cone as it moves.
• If you're a healer and ARE NOT targetted with a blue or red beam: Get into the blue cone. Stand still close to the boss and heal your tits off.

2. Maze phase. This is the phase that is killing us like crazy, and to be really honest, that's silly. Except (I think) for tank damage almost all other damage is completely avoidable. Moreover, standing in an eyesore for a tick won't kill you. Repeated fails do kill you. I'm happy that heals have figured out a way to blow CDs here to keep people up more easily, however, they simply shouldn't need to be blown, maze phase is a low damage phase. Healers should be able to regen mana during it and focus on running the maze. I'm guessing that our healer deaths here are partially coming from trying to heal people who take damage while they're trying to run the maze themselves. Honestly, we probably just need to stop keeping people alive who are taking damage. I have one tip for this phase:

• Don't panic. Seriously. When you panic you make bad decisions and die. There are no dead ends in the maze, just wait for the maze to open up.

3. Life Drain. On an average attempt, the Durumu is healing too much from Life Drain. Our mechanisms for dealing with it are fine. Usually we do well on it; however, we need for melee dps to never accidentially interrupt a beam close to the boss. When that happens, we're not prepared--and sometimes not able--to interrupt the beam. You will probably die and the boss will probably heal a lot.

• Think of Life Drain like a force of will. When you see the beam spawn, move away from it completely.

If we can do these things properly, we probably won't even have to do our mad burn strategy on the third light phase, we could even just do it normally and kill the boss during that phase. To achieve this, everyone needs to know what's happening and execute their roles properly. Mistakes are going to happen, but for this fight, having 20 people who know the strategy well and 5 people who don't will result in a wipe 90% of the time. It's not a fight that you can out gear easily.

It's totally doable.