Theck, the bringer of numbers, posted another of his patented analysis threads based on armor, and in particular, inspired by the Glyph of Indomitability. Some readers will remember that I recommended the Glyph to newer tanks in my post on Chill of the Throne. However, I made a caveat.
However, the glyph is absolutely useless on fights where the majority of theWrathy, Rhidach, and Honors have all posted their thoughts on the meaning of Theck's analysis with regards to dogmatic protection paladin theory. This post has kind of turned the ideas behind the predominant effective health formulas on its ear.
damage is magical in nature.
However, the conclusions were something that I already had a good idea of, and I'm fairly certain that any of the more cerebral tanks in the game already had a pretty good idea of too. What Theck's analysis has done is empirically prove what we've known all along. That currently slavish dedication to a single ideal of effective health is the wrong way of going about things. Variations in encounter design and damage sources creates variables that the old 11 armor=1 stam effective health equation simply does not accurately map.
In order to determine the best gearing philosophy, it has to be done on an encounter by encounter basis. It also requires an understanding of the limitations of each form of survivability, and their impact on encounter mechanics. A tank has several forms of survivability.
Flat damage mitigation: This is typically involves talents and cooldowns. This is advantageous because it works on all forms of damage. However, it cannot mitigate damage in its entirety, you will be hit through this, and some fight mechanics, which are predicated upon you taking damage, will still remain dangerous regardless of how much flat damage mitigation you have.
Avoidance: Dodge, Parry, and Miss. Each has certain advantages with regards to itemization, however, with the exception of miss, none of these work on non physical attacks. The benefits of avoidance is that it occasionally provides 100% mitigation from melee attacks, which are often the biggest source of incoming damage on most fights. This means that any debuffs associated with melee hits won't land either. However, this suffers from a lack of predictability, leading to healer panic attacks, and straight up ineffectiveness against many different mechanics.
Expertise: Expertise is usually considered a threat stat, and it certainly is, however, against many mobs, it works almost as well as dodge in regards to reducing incoming damage. Once again, Theck brought the numbers. It's kinda like the anti-dodge. Whereas dodge makes the mob attack and not hit you, expertise simply makes the mob not swing at you. However, this has all the limitations of dodge, and another big one. Against certain mobs, Gormak the Impaler and Patchwerk being among the more famous, they don't parry haste at all. In those encounters, expertise does absolutely nothing to improve survivability.
Armor: Armor is flat damage reduction that only works against physical damage. It has all the strengths and weaknesses of flat DR, but also becomes absolutely useless in the face of magic damage.
Stamina: Stamina works by directly increasing a tank health pool. It works equally against magic and physical damage, does not suffer diminishing returns, and scales blessing of kings. It sounds like a delicious panacea, and in some regards, it is. However, it is a statistic that is subject to "magic numbers". The point of stam that lets you go from being two shot to three shot is so much more important than any point since the one that let you stop being one shot by the boss. What the majority of the points in between do is simply make for smaller overkill numbers. It does help with healer strain, but different itemization theory can sometimes be a smarter way to go when you find yourself in the wasteland between those magic numbers. However, while the situations where more stam is actually detrimental are very few and far between, they do exist. Fights with mechanics that scale off health can create a harder healing load. The most prominent example is Anub'Arak's leeching swarm.
Resistances: Resistances are a much more difficult thing to decide upon. If stacked, the right resistances can almost completely mitigate some of the hardest hitting magic abilities in the game. However, it does nothing against anything else. It's also on very specialized gear which asks you to make severe sacrifices in exchange for that resistance.
One finds the optimal balance of stats for an encounter by looking at the mechanics of the fight. You have to look for what kind of sources of damage there are, which ones can be avoided, which can be mitigated by armor, which will require cooldown coordination. One of the most important things to affect your gearing decision is the choke point of the fight, the point at which you are at your most vulnerable. For example, Gormak the Impaler is the choke point for tanks from an itemization standpoint. You need to ensure you can survive the impale DoT melee combo, and while phase two and phase three contain a good amount of magic damage, armor is still a strong choice for itemization due to the fact that Gormak is the biggest threat, and all the magic mitigation in the world doesn't save you when gormak punches you in the chops.
I suppose that someone with far more time and inclination than myself could analyze the parses of those encounters, and determine the choke points in the fights. Then they could theoretically refine that information into an effective health formula that takes into account all forms of survivability weighted by usefulness. The coefficients would change based on each encounter, and give us a valid mathematical setup for the gear set.
However, that's beyond something I feel like doing, so until then, all I can suggest is that instead of mindlessly adhering to the EH formula, do your own research on the encounter, and make educated decisions. Don't be the tank shunning avoidance for Deathbringer.