Any block fix requires a 100% block rate

Think about it this way.

Avoidance is good because it removes a lot of damage. Avoidance is bad because it is unpredictable. If you stack too much avoidance, you are likely to give your healers coronaries.

Mitigation (armor and straight damage reduction) is good because it's consistent. As you all point out, you can start to learn how much a blow will actually do to you. Mitigation is bad, from a player's perspective, because it can't save you. If you have 10 health and dodge, you might live. If you have 10 health and hope your armor will save you... well, it won't. You become the dreaded mana sponge because you are never avoiding damage completely.

Mitigation also has a risk from a design-perspective that when fights get too predictable they become too easy and unexciting. Imagine a tank with 75% damage reduction and no avoidance. You could calculate from the moment of the first attack whether you will survive the encounter. Heck, you might be able to not even heal the tank and know you'll survive depending on the specific abilities used by the boss.

Block as a mechanic is somewhere between avoidance and mitigation. Ideally it removes a fair amount of damage (vs. all damage) reasonably often (vs. rarely). If block is up 100% of the time it just becomes armor that you improve through a different stat. We have let block chances creep up frankly because the amount blocked is pretty trivial when bosses are hitting for 40% of your health pool every swing. If this still strikes you as too RNG, imagine abilities like Shield Block and Holy Shield that could guarantee 100% chance to block for a short period of time.

We don't think block is cutting it as a mechanic, but the direction we are likely to take it is probably more of a change than you are considering.

We also don't think it's necessary that every tank rely on avoidance, block and mitigation in equal amounts. They can't get too far apart or someone will come to dominate for certain encounters, but we don't think the tanks need to be completely homogenized to get what we want either.

If (to make up numbers) the DK and druid get hit for 20K every swing that hits, but the warrior and paladin get hit for 24K half the time and 16K half the time, then that seems like it would work. When the boss emoted that his big hit was coming, you could make sure you had your cooldown ready to guarantee a block.

Take my examples with a grain of salt. I think some of you are trying to plug them in to today's encounters without changing anything else.

I agree that nobody wants to be the tank that avoids, avoids, avoids and then gets hit for 4X normal damage. (Then again, part of the problem we had with DKs last patch was their avoidance was just too high.) In my example, the shield-using tanks get hit for 4K more damage 50% of the time. If you're calling that "spike damage" and saying it's unacceptable, then I'm afraid nothing can be done to salvage differences among the tank classes.

Q u o t e:
Differences in effective health of that magnitude (8K over 2 hits, 15% of a tanks health) probably breaks the tanking game. Current encounter design probably places too much emphasis on effective health for effective health to vary much across tanks.

That's why the major balancing points for tanks is armor X health (EH) and cooldowns. Tanks can vary more in terms of effective health if you switch encounter stress away from effective health. It would require a paradigm shift in encounter design.

Yes, this is why I said not to assume everything else stays the same. We are in a world where almost any healer can heal a tank to full health in just a few GCDs. When healers can heal half your health pool, then bosses have to hit very hard. The test of survival for a tank is whether they can survive two hits or so without a heal landing. Health pools probably just need to be higher. Currently being the mana sponge tank isn't very scary because healers don't realistically run out of mana on most fights and the only real threat is whether you can get the tank back up to 100% before the next hit lands. Mitigating damage isn't seen as something that preserves healer mana. It is seen as something that might let you live through one more hit.

In a world where taking a little less on some hits and a little more on others doesn't translate into scary spike damage, then we think the block mechanic described above world work in some form, especially if you could force a block for those times when you did get a string of unblocked hits.

Q u o t e:
How is what is being said any different than the crushing blow discussions in Burning Crusade?

Crushing blows hit for 150% of normal damage. So a 20K hit normal hit would be an unpredictable 30K crushing blow. If crushing blows were 120% of normal, but you also had an equal chance for an 80% of normal hit, then it would even out in the end... provided that the spikes were not too big.

It may also be that the blockers would need to take even less damage when blocking because there is some merit to the argument that the tank with the lower variance on damage is easier (or at least more attractive) to heal even if the averages came out the same.

However, we are still just going to reject the notion that anything with an RNG component is unacceptable (provided you have the tools to occasionally get by when you get unlucky). I can totally understand as a player why it's in your best interest to minimize the RNG when tanking. You can also understand, I hope, why it is not in our best interest.

As I said above, once you can totally math out how much damage you're going to predictably take at the start of the fight, it will absolutely be an easier fight to tank... probably to the point of boredom. Imagine the 0% avoidance, 90% mitigation tank in a land in which bosses can never crit or crush. Is that going to be an effective tank? Yes. It it going to be fun to play? I doubt it.

Q u o t e:
Still you are increasing the spikes of Warriors and Paladins. You can lower the total damage of the blocked, but the problem is the unblocked. If you are taking a 24k hit when a druid will always take 20k hit, then you are stressing the healers, who have to be ready.

And then the warrior blocks and takes 16K and the druid is stressing the healers with the 20K hit.

I acknowledged healers might have to be on their toes when hits are sometimes big and sometimes little, but that is already the case given that all 4 tanks have a non-trivial amount of miss, dodge and sometimes parry.

Q u o t e:
So why not have the tanks who use block for the RNG mitigation have more HP?

This way their damage is spikier but they have a bigger cushion? This was the druid design in TBC and while crushing was too much of a variance, with the much smaller blocked vs non-blocked a small HP pad would work nicely.

We might have to increase the health to compensate. Just don't use the BC druid too much as role-model. They became so powerful that we had to add Sunwell Radiance. :(

Q u o t e:
With the current design of half the mobs we've seen in Wrath (since Naxx was designed pre-wrath), you've been giving tanks these massive attacks to deal with. Mitigation over time is largely irrelevant. If you added another 20% spike to the tanks that already have no way to deal with the in-game designed splikes, you're not helping. You'd be making the already less desirable tanks even less desirable!

I don't buy that mitigation over time is largely irrelevant. I'll buy that cooldowns during big magic damage are very important. Are you saying you only ever lose tanks during the Plasma Blast-esque attacks?

Q u o t e:
The problem with the RNG is not the situation you're talking about. It's not the variable normal damage that averages out. It's when the big hit is incoming that the tank will barely survive. The encounter is designed so that this hit is very hard. Now that RNG is not "Tank needs a bit more healing", but is "Tank is dead due to RNG". The latter case really sucks. Wiping the raid because of RNG is bad. This is why tanks that have spikey damage are shunned. The tank is the lynchpin of the raid. Letting the RNG-monster wipe the entire raid isn't fun. The "bad side" of the RNG becomes much more powerful with the way tanking works. A hundred "good side" or less damage RNG results, followed by one bad, means that the tank will never be brought, because that one bad will get the tank killed, and a dead tank is a dead raid. 20% more damage will cause the boss to one-shot me in several places in Ulduar.

As I tried to explain above, this is player thinking. "Must minimize RNG in order to survive" is good for the tank. It's bad for the game. You become very, very effective and the fights are very boring. We might as well not have bosses do normal swings at all and just make tanking where you stand around for 60 seconds and then use a cooldown during the Plasma Blast. Our goal is to make you try and minimize the effects of RNG. The RNG is the obstacle you need to overcome. We aren't going to remove that obstacle in order to help you overcome it more easily.

Q u o t e:
Let me give you an example: If you were to double the hp of current tanks and bosses, the fights would be turned into a mitigation/healer-mana attrition situation. In a case like that, the tank is never in fear of being one-shotted or even two-shotted. In that case, a spikey RNG would introduce an element of random fun and keep things from being too stale.

I think the game would probably feel better like that too. (PvP even!) Lesson learned.

I wonder though -- would you just be able to get away with half as many healers, knowing that you can afford to spend two GCDs every hit to get the tank back up? If they risked running OOM, that might be the case.

Q u o t e:
I'm sorry but have you raided Ulduar at all? Tanks die the majority of the time to one of 2 things, burst damage from the boss (aka plasma blast) or healers forced to move out of position. If they die to anything else then your healers were asleep and that is there fault.

When has that not been the case in WoW though? The only other situation is when you just fail a gear check because the tank takes too much damage, your dps can't beat the enrage, or your healers can't heal fast enough. We just used to call the burst damage from the boss strings of non-dodges or crushing blows.

Q u o t e:
I'm not sure I see how that would change the issue. You say the RNG is an obstacle to overcome. Fair enough. But it seems like the simplest way to overcome it would be to chose a Druid or DK. If you have 4 tanks, 2 are affected by the RNG by say, 10%, and 2 are affected by 20%, but on average they avoid and mitigate the same, you'll just go with the 10% tanks.

I never said avoidance and mitigation (or health) would have to stay the same. The goal here is to bring back block.

Q u o t e:
This strikes me as a massive misunderstanding of what actually kills tanks. DKs, druids and even paladins currently enjoy the simple fact that when a boss hits them, they and their healers know roughly how much damage that hit is going to do. Warriors currently have no clue how hard a boss is going to hit them; they can be completely unblocked and take a series of full damage attacks or they can have a string of shield block critical and knock 3k off each hit. This spike damage is completely unpredictable and significantly harder to heal.

The problem I have with this kind of argument is you're basically saying that avoidance is awesome and mitigation is awesome, but something with aspects of both can never work. I would argue that no tank has a clue of how hard the boss can hit them because they can dodge 30 attacks in a row under a blue moon. However, because you are removing so much damage every time you avoid, we all still use avoidance despite its random nature.

A wise tank said to me recently: imagine the block coming at the expense of avoidance instead of mitigation. Now imagine you block a lot more often than the other guy can dodge. If anything, the block tank is going to be less spiky than the non-block tank.

Q u o t e:
Even that may not be enough. That's largely the decision faced in BC; warriors took spiker damage, often less overall. Druids took more, but predictably. Healers favored the predictability, even when it meant they had to heal harder, because it was consistent.

There is an element of truth to this. However, druids will also tell you (because they tell me all the time) that they don't want to be the mana sponge tank. Healers tell them that maybe they are easier to heal, but they can also risk draining them dry. That may not be an issue on normal modes, but healers do seem to be running out on hard modes (maybe not paladins).

Q u o t e:
I don't understand why block value cannot be changed to a percentage of physical damage blocked versus (currently), a static amount.

The problem is always going to be buffing block value for raid encounters and balancing it around PvP. If it's too high, it becomes effective on bosses but OP on melee classes in pvp. If it's too low, it works in pvp, but completely useless in pve.

Changing block to a percentage of physical damage "absorbed" keeps it properly scaled for PvP and PvE.
I don't buy the argument that Block value as a percentage is "armor" by any other name. It's not.

Armor is active all the time, whether hit from front or back, stunned or not. Block is a "proc," ineffective from behind or when stunned.

But your final example rarely happens in PvE. The tank is most likely not turning her back on the boss and not stunned. In this common scenario, block and armor are almost the same thing reached through different stats.

It might work but it's not terribly interesting. Most often one stat would always trump the other since they did the same thing. Compare say crit and haste as stats. They both improve your damage or healing, but in very different ways that have a lot of ramifications on talents and rotations.

Q u o t e:
Another Note about Blocking as a EH or mitigation stat.

It does not work when knocked down, facing away, incompasitated, stunned, etc...

These events happen... its a double whammy because you also can't parry and dodge.

example: Auriaya, oops, running away now for 1/2 second, BOOM pounce+ boss hit... (not an issue for warrior tanks as much as pallies though for fear)

They happen, but very rarely. I'm not sure paladins for example would keep a high block stat vs. a high armor stat to account for differences in bosses stunning them.

Q u o t e:
It's 20k + 20K + 20K +20k (predictable)

vs.

16k + 24k + 24k +24k (bad luck = dead)

The change they propose, changes nothing.

You could just as easily say:

16K + 16K + 16K + 16K (good luck = alive)

vs.

20K + 20K + 20K + 20K (predictable, dead)

You're turning 24K into a magic number here. If the situation was:

Tank A: 16K + 20K + 16K + 20K
Tank B: 20K + 20K + 20K +20K

Then I don't think anyone would disagree that tank A is the safer tank. So what if the situation was:

Tank A: 12K + 21K + 12K + 21K
Tank B: 20K + 20K + 20K + 20K

Now who wins? A is taking more "spikes." Does more spikes always lose?

Q u o t e:
There are more ways to make a fight interesting than "Let's try to randomly kill the tank". When you rely on RNG mechanics, people are simply going to go to the class that is least affected by it. It's why you are seeing the gravitation towards DK tanks, because they are the best at fighting your RNG deaths.

Druids have the largest health pools. They logically would be the least RNG. I think players use DKs because of their cooldowns. That isn't an RNG issue. The attacks are often announced or on strict timers, and will usually kill anyone unless they use cooldowns. Block won't help with that and neither will large health pools unless they are insanely large.