Defense Theory II: PvE Defense for Tanks

With the Attack Table basics covered, here are the details for PvE defense – applied to tanks, because they’re the most focussed on mitigation here.

First things first, when tanking raid bosses, these are level 73, and this lowers your defense values seen in the paper doll in favour of the boss.

Now let’s go back to our PvE attack table and look what values we can play with and how:

Miss
Dodge
Parry
Block
Critical Strike
Crushing Blow
Normal Hit

Critical Strike is a simple calculation of attack skill vs defense skill, and from a raid boss you have a base 5.6% chance of getting critted. The interesting part here, though, is that by raising your defense skill, you will (among others) be able to narrow down this 5.6% chance to nothing.
For Warriors and Paladins, that’s 490 defense you’ll need, at that point you will have become uncrittable.
Druids have a feral talent called Survival of the Fittest which immediately narrows the Critical Strike gap by 3%, down to 2.6% – which means Druids will only require 415 Defense Skill in order to reach uncrittable status.

That’s the most dangerous damage source taken care of. Now some will ask why not use resilience as a means to become uncrittable. This is simply because stacking Defense Rating instead of Resilience will not only help you towards uncrittability, it will also at the same time raise your chance to be missed, to dodge, parry and block. So stacking Defense is immensely preferrable in terms of benefits offered in order to address those 5.6% crit chance, for warriors and paladins. For druids, the matter is less clearcut, since they cannot parry or block. While purely in theory Defense remains more beneficial (as it raises dodge and chance to be missed along with uncrittability), high end bears suffer from big itemization gaps, and may be forced, past T4 content, to resort to PvP gear to maintain uncrittability.

Crushing Blows is a different story though. As explained previously, Crushing Blow chance is a set number based upon the difference in levels between you and the mob you’re tanking. Contrary to the Critical Strike chance which can get narrowed down to 0, you cannot “compress” the Crushing Blow range on the attack table.

We’ll leave this on the side for a moment, and look at how Normal Hits behave. As we’ve seen, Normal Hits simply take up whatever space there is in the Attack Table between the sum of all other entries and 100%. The higher the sum of the rest, the less room there is left for Normal Hits. Once the other entries added together reach 100%, there’s no room left at all for Normal Hits, only Crushing Blows and Crits will get through (provided you’re not uncrittable yet), the rest will be either blocked, parried, dodged or simply missed. You will have “pushed Normal Hits off the Table”.

And once you’ve done that, if you raise total miss plus dodge plus parry plus block chance any further, you will effectively start pushing Crushing Blows off the Attack Table as well. How’s that? Simple. Remember, we roll a /random 100. If the other entries add up to 90%, the Crushing Blows range is 91-105%, which means the top 5% are outside of the range of the results our die roll can reach.
So once the sum of all other entries reach 100%, we will have effectively pushed the entire range of Crushing Blows off the Attack Table, and become Uncrushable. To be more precise, we need to account for the level difference with a level 73 boss, which means your total Miss + Dodge + Parry + Block has to be 102.4% instead of 100%.

How to get there is a different story though, and it varies by class.
For a protection Warrior, it’s most straightforward. With Shield Block up, you add 75% to your Block chance for 2 hits within 5 seconds. So the sum of your Miss + Dodge + Parry + Base Block needs only to be 25%, something you have already when you’re uncrittable. There’s a caveat on fast hitting bosses though, accounting for lag, any boss with faster than 2.0 speed may land a Crushing Blow every now and then.

For paladins, it’s a lot tougher – pallies get (improved) Holy Shield, which adds 30% Block chance for 8 hits over 10 seconds. There’s also a libram (Libram of Repentance) around which grants another 5.3% chance to Holy Shield. The rest has to come from gear bonuses, either by stacking straight Defense Rating (preferred choice as it will boost all other values) or individual ratings, with preference for Dodge and Parry, or any viable combination of everything.

For Druids, it’s a different story altogether. They cannot block nor parry, so there is currently no gear combination in the game which allows them to become uncrushable. What Druids will strive to do instead is to load up on stamina in order to soak up those Crushing Blows when they happen, and on armor in order to mitigate whatever damage gets through.

The figure below illustrates all of this:

These mechanisms also position the inherent strengths and weaknesses of all tanking classes. A druid will stay crushable and will require heavy healing when one gets through. Hoever, they have the most stamina in order to ensure they can survive any crushing blows while the healers get them back up into shape.
The paladin is currently in the worst situation in regards to Crushing Blows: where a warrior is uncrushable “by default” and can start stacking stamina, complete avoidance (Miss, Dodge or Parry) or resistance on his gear, a pallie will have to cover the 40% (45% without the Libram) gap to uncrushability. On top of this, the pallie will also require some spell damage, as his threat comes from holy spells.
What’s holding a paladin back in terms of raid boss tanking isn’t skills or aggro generation, it’s simply that itemization values on current gear leave him at a disadvantage vs both a Druid and a Warrior.Does that mean pallies are unfit for the job? Nope. By many accounts, uncrittable and uncrushable pallies do the trick in Kara, in Gruul, and apparently even in SSC. But beyond that, the itemization problem becomes, at present, unsolvable for them. On the plus side, for all the instances where pallies can tank, be it heroics or the first raids, they bring 8 blocks over 10 seconds of uncrushability, which leaves them less open than a warrior to an unlucky Crush going through at the wrong moment.

There are of course other elements in terms of comparing the three tanks but that’s the scope for a different post, on some other day.