Hey there! I want to discuss the warlock spec DM/Ruin. People say it's inferior to DS/Ruin, what with losing out on a few sweetass points in Cataclysm, and Improved Life Tap. But hey, as DM/Ruin you can keep your pet alive, and it does DPS too. I've been crunching some numbers that I want to share when I can create a nice enough overview, but a variable remains - how easy is it for your pet to die? Is it 1/10 boss fights it survives? Is it like 50/50? Or does it only die in a small handful of bossfights, but when it does it happens so fast people are like wtfbbq it's useless?

Does anyone have any experience with this?

Pets did not have resistance to AoE damage. They die really fast. You either https://classic.wowhead.com/spell=4511/phase-shift (for https://classic.wowhead.com/spell=11767/blood-pact, especially if you're running Improved Blood Pact) - or you sacrifice it for the extra Shadow damage.

Depending on the boss (and patch I think), they can be subjected to mechanics. So even if it were to work on a very theoretical level, it would be very contextual and silly. Talents such as Improved Life Tap are far more important, especially since you will be using it a lot.

You're free to consult with the Warlocks on the Classic Warlock server but I doubt it's viable.

But are there only a handful of bosses with little to no AoE mechanics? Off the top of my head I can only think of patchwerk, but he's so far into progression that DS/Ruin definitely is better. But there must be others?
From my limited vanilla raiding experience I learnt that the pace is rather slower, and on, say, Lucifron, a ranged DPS without healing lasts a minute or two.

Is it imaginable that even if it's sub-optimal to spec DM/Ruin in a normal, new guild that takes several simutes per kill, it is not so in a speedrun guild where you squeeze out as much DPS as you can and barely take damage? (Pardon my limited knowledge here, haven't speedrun at all before, so I don't know how much damage they take...)

dm ruin meaning master demonology/ruin? That is a viable post bwl spec as the imp threat reduction can increase lock dps a lot. there's no need for the mana from cataclysm as you will be kept alive while lifetapping if your raid team has proper healing as well as you can use pots and even lifedrain to restore your life as situationally appropriate. The only specs i've seen ran by top raiding locks are sm/ruin, ds/ruin, and Master Demonology/ruin. As to using your pet goes it is possible in many fights but you have to micromanage (effectively keybind) your pet and play it well. It also helps to make sure your healers are willing to heal pets. That requires great healers and great play on the part of the lock.

Raids in Classic normally run a warlock with improved imp anyways but I'm pretty sure SM/ruin is better than DM/Ruin so that one warlock will most likely run that instead.

What is DM/Ruin? Can you link the build?

I am only really familiar with SM/Ruin and DS/Ruin. SM/Ruin is where you keep your Imp out. This spec is used for the tank group. DS/Ruin should provide slightly higher personal DPS at the cost of not having a pet.