The Basics: Armors
Right, so you can't have any talk about warlock survivability without dragging Fel and Demon Armor into the discussion. Now, to first focus on the PVE side of things, Fel Armor is liable to be the armor of choice. Do remember, though, that there is a time and a place to utilize Demon Armor, even in PVE.
Armors are the backbone of any cloth caster's defensive toolkit. Mages have armors, and even priests have their new flashy abilities that replicate armor effects. While damage is the objective that people zero in most on in PVE, it isn't your only goal; you also have to care quite a lot about the whole staying alive thing. It's pretty important, too.
In terms of damage, of course, Fel Armor is easily the best out of all of the armors available to any class. Fel Armor directly increases spellpower, which is something that mages don't know from any of their armors. That right there puts it well above anything that a mage could even dream of using. Inner Fire from priests also increases spellpower, but it gives less of it than our defensive tool does. I call this a solid win for the warlock department.
Its raw defensive abilities get a little bit trickier to define. Fel Armor doesn't have a defensive mechanic per se; instead, it allows you to regenerate 3% of all of the single-target damage that you deal. It can be quite easy to scoff at 3% as a trivial amount; perhaps it is. Assuming that you are capable of dealing 20,000 single-target DPS, then you would similarly be healing yourself for 600 HPS. Worth it? Probably not.
Fel Armor doesn't exist to try and give warlocks massive amounts of health return but instead to counteract the amount of self-inflicted damage that they deal. That's a decently fair trade-off when you look at it, but how practical is it? Life Tap is going to hit your health in one large "burst," whereas your health is only going to trickle back from Fel Armor. It might be balanced in the long run, but you'll just have healers negating the process through simply doing their jobs.
The other thing about the health return from Fel Armor that's upsetting, to me at least, is that Vampiric Embrace has a higher self-return. Shadow priests don't deal nearly as much damage to themselves as warlocks do; our armor should return just as much health to us as their silly little ... buff returns to them. It seems only fair.
On a plus note, Fel Armor is way more defensive than Molten Armor for mages is. Molten Armor provides the mage with a 5% chance to not be critically hit, which doesn't help them in PVE at all. Unless they start thinking they can tank a boss -- P.S., they can't -- nothing that will hit them is even capable of critting. We win this round.
Defensive utility of armors
Fel armor might have a rather decent use in PVE, but the downside of our armors really comes out in PVP. That isn't entirely true -- Demon Armor is a rather good choice for armor in PVP, and I would strongly suggest that you use it, unless you think that 3% health return from Fel Armor is going to outheal a rogue.
Demon Armor is a pretty sweet deal for PVP, but it does rely on having an actual healer around. In random queues, this may not always be possible, but you should never be without a healer in organized PVP; the exception is when you're running a double DPS 2v2 comp.
Comparatively, though, does Demon Armor really hold up against those of other classes? It's a tough call. In terms of damage mitigation, Demon Armor is actually the worst of all of the choices out there. Frost Armor reduces physical damage by 15%, while Inner Fire increases armor values by 60%. Both are different bonuses, but both are also above and beyond better than the 2,345 armor granted by Demon Armor. (As a side note: Really, Blizzard? Really? 2,345? Sequential order -- is that how we create spells now?)
Regardless of which of the three armors is the worst, it should kind of be noted that all of them are actually pretty bad. Physical damage is nothing but a different spell school that's pretty much as useful as Shadow Ward. There are only three things in the game that you'll run into that rely exclusively on physical damage: warriors, feral druids and possibly retribution paladins (I can't recall how much of their damage is holy and how much is physical). Sub rogues rely pretty heavily on physical damage as well, which is a great thing for our armor, but they still have pretty high poison damage. Marksmen hunters are fairly physical damage-based, as well.
That is the growing flaw with armor itself. There are far too many physical DPSers that don't deal physical damage any more. Survival hunters only have Auto-Shots that deal physical damage; death knights are pretty evenly split between some form of magical and physical. Assassination rogues deal nearly as much nature damage as they deal physical damage. As these classes gain more abilities that ignore armor, the value of armor in PVP decreases.
Why armors are useless
There has always been an arms race of sorts between armor and armor penetration. Although Blizzard has since removed the actual stat to allow for players to penetrate armor, it can't remove the ability to do so completely. Magical damage totally ignores armor, which is the crux of why armor penetration grew so powerful.
When Blizzard looks at PVP, there's a certain limit to how much damage that the developers want for each class or spec to be able to do within any given time frame. Given that magical attacks all ignore armor, physical attacks have to be balances around the factor of armor, which is much stronger now than it ever was.
At the start of Cataclysm, Blizzard made a big to-do about how it was going to be rebalancing armor values. It understood that cloth and leather were just a little bit too squishy in comparison to plate, and even mail was a little bit lacking. Yet the entire idea that this "solution" actually solved any form of problem is a fallacy; it ultimately didn't hold a large impact in reducing the overall physical damage than players take in PVP.
Why? Simple: Blizzard has expected values of damage that it wants for players to be able to deal. While Blizzard now has more freedom to increase the damage that warriors and the like are capable of dealing to high-armor targets without it causing them to utterly demolish low-armor targets, the overall damage output of a warrior really wasn't going to change -- and it hasn't. Warriors are still a really strong PVP class that deals punishing amounts of damage; rogues are still a powerful PVP class that can deal massive amounts of damage.
When it comes to survivability, everything is rather meaningless. Blizzard expects a certain amount of damage to be dealt. Passive damage reduction is a virtually useless stat in PVP. It does not exist to actually increase your expected survivability in PVP; it exists to allow Blizzard a tool to balance damage between PVE and PVP, wherein PVE damage is vastly higher.
Think of it this way: 20,000 damage per second is far too much for any player to be able to deal in PVP. A blanket silence, a single stun, and someone is going to go from 100% to dead before you can get out. So we want to reduce PVP damage. What's the best way to do that? Passive damage reduction. Toss in a talent for players, or give them some ability or another that just says "reduces the damage you take by 20%," and your problem is solved. Now you have two tools that you can adjust to tweak PVP damage -- the damage output itself and the damage reduction of players.
How to save a life
Passive damage reduction is important because you are expected to have it, but it isn't what will actually save your life in PVP combat. Again, everyone is expected to have whatever passive damage reduction effects that they can, so Blizzard balances PVP damage around that assumption. This is one of the primary reasons that raw defensive and escape mechanics are far more important than passive damage reduction.
Having the ability to temporarily drastically increase your damage reduction or to escape and avoid all incoming damage completely will always be the best defensive mechanic. This is because it's an intangible effect that you can't directly balance against. You cannot look at abilities such as Barkskin and say "Oh, it provides an average of 8% damage reduction." No, it doesn't. It provides 20% damage reduction for 12 seconds.
This is actually quite the downside for warlocks defensively, and it really shows why affliction does so well. We lack a lot of these defensive tools as baseline abilities. There's Demonic Teleport, but that is all we really have in terms of damage mitigating abilities; instead our focus seems to be more on passive damage reduction.
For example, when fighting a warrior, it is expected that you would have Curse of Weakness and Soul Link up, which would put a rather good dent in the damage that you take. Curse of Weakness is fairly strong, yet it too suffers form the same issue that it only reduces physical damage.
Warlocks do not escape damage as much as they are expected to tank damage, and they don't rely so much on damage reduction tools as they rely on a mixture of damage reduction, self-healing, and a passive increase to healing received. Theoretically, this is a great system; it's different than what you see for other casters, it's rather interesting, and it can be functional. The problem, however, is that only affliction really supports this.
Each spec has its own self-healing talent. Affliction has Siphon Life, destruction has Soul Leech, and demonology has Demonic Aegis. Realistically, it feels as though destruction should be the best in terms of self-healing; they can get the most damage talents while getting both Soul Leech and Siphon Life. This isn't the case.
Siphon Life is highly powerful, but the real draw of affliction isn't the ability to tank damage. Warlocks are designed to do this at a base. No spec is really much better at it than any of the others, yet affliction is better at putting out pressure and at avoiding damage, which is far more important.
Despite being designed to tank damage, tanking damage is a a flawed concept. Avoiding damage will always be vastly superior. The spec that is best able to avoid damage while dealing it at the same time will be the best PVP, and that is exactly what we see.
Blood Pact is a weekly column detailing DoTs, demons and all the dastardly deeds done by warlocks. We'll coach you in the fine art of staying alive, help pick the best target for Dark Intent, and steer you through encounters such as Blackwing Descent and The Bastion of Twilight.