Considering that 5.2 is on the horizon with a PTR available, it's probably a bit late to be doing this but it's something I want to do for each tier. I'm assuming that most progression focused warlocks have already cleared MSV at this point and don't have a particular need for this information but it still might be handy for the more casual raiders or maybe someone who's gearing up a warlock alt.
Full guides to each raid boss can be found all over the internet or YouTube so this is just going to be some basic warlock specific tips and recommendations regarding specs, talents and techniques. Heart of Fear and Terrace editions will follow as my guild's progression allows.
For reference, this is the basic setup I'll use for any given fight before making any boss specific adjustments.
Talents: Soul Leech, Mortal Coil, Dark Bargain, Burning Rush, Grimoire of Sacrifice (Voidwalker), Kil'jaeden's Cunning
Glyphs: Healthstone, Burning Embers, Siphon Life
Spec - Demo or Affliction
Talents - Dark Bargain or Soul Link, Unbound Will, Archimonde's Vengeance or Kil'jaeden's Cunning
This is mainly a two target fight. Refresh dots as a dog is being taunted away for extra generation/procs, but don't bother maintaining them once it's pulled off. Roll dots on both active targets as much as possible. Demo's splash AoE from Hand of Gul'dan and the Felguard are particularly strong here since your targets will be right on top of each other, giving it the edge over Destro, but Affliction still has the upper hand as it does on most council fights.
Spec - Whatever you're comfortable with
Talent Choice - Dark Regen or Soul Leech, Dark Bargain or Soul Link, Archimonde's Vengeance
This is a strictly single target fight so Mannoroth's Fury is worthless here and not a huge amount of movement, giving Archimonde's Vengeance the edge. A fair amount of passive raid damage with big bursts makes the passive survival talents as viable as the active cooldowns.
Spec - Prefer Destro or Affliction for the Spirit Realm
Talent Choice - Harvest Life, Archimonde's Vengeance
Arguments can be made for any of the first tier talents, but Harvest Life is particularly handy in the Spirit Realm especially towards the end of the fight when there are a lot of adds in there. There's very little movement and multi-dotting is more effective than AoE in the Spirit Realm, so Archimonde's Vengeance is the best choice here.
Spec - Whatever you're comfortable with.
Talent - Harvest Life, Kil'jaeden's Cunning
Harvest Life is a fantastic way to AoE your mind controlled raid members without hitting them with DoTs. The fact that it adds some passive healing to you at the same time will take some pressure off of your healers. It may be worth taking Unbound Will over Burning Rush, but with so much movement throughout the whole fight and only one phase where Unbound Will may be used, I'd rather have the movement speed. Supremacy pets are also a viable option since you'll spend so much time dodging things. Most of the really deadly raid damage is avoidable and AoE isn't a concern, so Kil'jaeden's Cunning wins out.
Spec - Destro or Affliction
Talents - KJC/AV/MF depending on where your assigned spot is during orb phase and if you're having trouble with adds or the enrage timer
Destro has the easiest time of orbs in my experience. Demo's reliance on pets and Affliction's ramp-up time make them sketchy while Destro can almost one shot them with a Backdraft driven Chaos Bolt. While our Affliction warlock (who heavily outgeared me at the time and generally can out-DPS me simply by spec choice) was having trouble with the third orb, I was breezing through four and asking for a fifth. Havoc the boss or a second orb to really tear it up.
You can't place a portal or gateway anywhere on the center floor area, but you can place them in any designated stacking point. Having a portal at the very edge will allow you to quickly drop your stacks during the final burn if you need to. There is also a sweet spot around the edge of the ring where you can jump in place to clear your stacks. Standing in this spot while specced into Kil'jaeden's cunning means you can clear your stacks with absolutely no DPS loss.
Will of the Emperor:
Spec - Destro or Affliction
Talents - Dark Regen, Archimonde's Vengeance or Kil'jaeden's Cunning
Will swaps between a two-target and multi-target fight, but targets are typically too spread out for Demo to cleave effectively. Abusing Havoc and Shadowburn is really effective while Affliction can roll dots on both bosses and the current kill target. Dark Regen tends to be stronger than Soul Leech here because the bulk of raid damage will be during gas phase. AV is also nice during the gas phase, but KJC gives you the extra "GTFO" ability for when you really need to get moving.