Just wanted to help out the community a bit and specifically my warlock bros and our dealing with an 8 debuff limit. I'm gonna take a second a talk about how debuff prioritization is supposed to work before giving you the (what I and Exiled call) ideal raiding warlock build.
Debuffs work on a system of 5 prioritizations. The higher priority debuff will always knock off a lower priority debuff and works upwards from the bottom. A Taunt will try to knock off a trash debuff (Deeps Wounds, Fireball Dot) then a DoT (Corruption, SW:P) then a Medium (Vulnerabilities, Ignite, Vamp Embrace) then a High (Curses, Sunder, Demo, Thunderclap) if the debuff limit has already been reached.
Highest:
- CC / Roots (Sheep / Seduce / Sap / Gouge / Frost Nova etc)
Taunt effects (Taunt, Mocking Block) (I've also read somewhere that Taunts get a special bonus debuff slots but can't confirm that)
High:
- Curses
Sunder
Tclap / Thunderfury
Demo
Faerie Fire
Hunter's Mark
Judgements
Medium:
- Vulnerabilities (Winter's Chill, Shadow Weaving, etc)
Ignite
Gift of Arthas
Vamp Embrace
Hunter Stings
Deadly Poison
Mortal Strike
Low:
DoTs, Longer duration = high priority
Trash:
Fireball Dot, Deep Wounds, weapon proc debuffs
That brings us to warlocks. In retail vanilla, the prevailing thought was SM/Ruin (30/0/21) was king. Keep corruption up and spam shadowbolts getting those nightfall procs. However, the DS/Ruin (7/21/23) spec actually out preforms SM/Ruin on single target fights. The talent builds are linked at the bottom. However, your raid will still desire an Imp for the tank group and this warlock should keep the SM/Ruin build but doesn't get to corruption the main targets. You can (and should) corruption adds that aren't being focused - Golemagg, Domo, Sulfuron, Garr - to get those nightfall procs but you cannot (and likely will not be able to) corruption the main target. Ultimately, this warlock will likely lose about 7-8% dps than it normally would if it was able to corruption.
With the DS/Ruin build you're basically a shadow version of a frost mage; you simply spam shadowbolt and lifetap when needed. What is great about this is that you don't need any debuffs to maximize your DPS; in fact, if you spent a global cooldown trying to apply a DoT you'd actually be hurting yourself.
I hope this helps the community and keeps my warlock bros from crying themselves to sleep over not being able to dot anything.
DS/Ruin - http://db.vanillagaming.org/?talent#Ix0 ... hoZvx0tM0z
You can change around points with Improved Healthstone as the different point Healthstones stack. The points in Demonology can be moved around as long as you get Demonic Sacrifice, that's all you're here for. The points in Destruction are set in stone. Suppression vs. Imp Corruption is preference. With this spec you Sacrifice your succubus and shadowbolt spam.
SM/Ruin - http://db.vanillagaming.org/?talent#IE0bhRbkAZZgx0tM0z
This spec is the exact one I run. SM/Ruin has a little more flexibility in Affliction. You can move the 5 points in Improved Life Drain to Amplify Curse + Exhaustion, Imp Exhaustion (I do this as my guild's SM/Ruin lock as I like exhaustion for pvp and don't need to respec and amplify curse is useful for phase 2 Onyxia). You can also move the 3 points in Imp CoA and 2 points in Suppression to Weakness or Fel Concentration if you'd like that instead. All the other points are set in stone. With this spec, you keep your phased imp in range of the tank and shadowbolt spam. You can corruption non-focused adds for extra dps.