So let's look at what the Developer's have announced for changes to Tanks.
Bye Bye BlockWe've known since Ulduar that something needed to be done with Block. As Bosses hit harder and harder, Block became more and more useless. Then we got to Crusader's Coliseum, and we discovered the gimmick in the Anub'arak encounter that encouraged us to build a block centric set. Now in ICC Block is back to being something we get through other stats. We get our Block chance through Defense and our Block Value through Strength. We don’t seek it out, it just sort of comes along for the ride.
The long awaited answer to Block has finally been revealed by the Devs.
Block Rating - Block is being redesigned to scale better. Blocked attacks will simply hit for 30% less damage. Block rating will improve your chance to block, though overall block chances will be lower than they are today.
Shield Block Value - This stat will no longer be present on items, since the amount blocked is always proportional to the amount of damage done. Talents and other effects might still modify the damage-reduction percentage from 30%, however.
'other effects' probably refers to Trinkets or Procs. I'd expect we will see some changes to Redoubt and Holy Shield. Block becomes a percentage reduction instead of a flat amount. There won't be a need or ability to build a 'Block Value Set' in Cataclysm. We'll have to wait for the theorycraft to decide how we rank this new Block in with the new Parry and good old Dodge.
Defense - Defense is being removed from the game entirely. Tanking classes should expect to become uncrittable versus creatures just by shifting into Defensive Stance, Frost Presence, Bear Form, or by using Righteous Fury.
See that 'versus creatures'? I take that to mean that our Crit defense will be useless in PVP.
This will remove one of the major headaches tanks face when they first reach the level cap. It should also mean high end PVE gear will last much longer for Tanks in Cataclysm than it did in Wrath. I kept my Burning Crusade end game gear (Tier 6) all the way to level 80. The biggest reason I had to replace it with Saronite stuff was I needed massive amounts of Defense rating to get uncrittable. That won't be a problem in Cataclysm, so I would suspect that iLevel 277 gear should be useful in early Heroics, and perhaps even early raids at 85.
Final Nail for AvoidanceParry- Parry no longer provides 100% avoidance and no longer speeds up attacks. Instead, when you parry an attack, it and the next attack will each hit for 50% damage (assuming they hit at all). In other words, Dodge is a chance to avoid 100% of the damage from one attack, Parry is a chance to avoid 50% of the damage from two attacks, and Block is a chance to avoid 30% of the damage from one attack.
Parry is no longer Avoidance, but more like Block. With Defense gone and Parry reworked, the Block Cap, or what a classic tank called Uncrushable, is effectively put out of reach. Dodge is left as the only true Avoidance stat in the game. It will become much more valuable than Parry, yet right now Parry has the harsher Diminishing Return. I would expect to see that reversed and Dodge will get the harsher Diminishing Return in Cataclysm, meaning lower Dodge rates overall.
Gearing in Cataclysm is going to be a lot like gearing in Ice Crown Citadel. Armor and Stamina, which is traditional Effective Health, gearing will be what every tank does. Tanks will be damage soakers, not damage avoiders.
What Makes a Tank, a Tank?Armor - The way Armor mitigates damage is not changing, but the Armor stat has been rebalanced to mirror changes to the armor curve in Cataclysm. As a result, bonus Armor will go down slightly overall. We are also changing the mitigation difference among armor types so that plate doesn't offer so much more protection than mail, leather, and cloth.
Stamina - Because of the way we will be assigning Strength, Agility, and Intellect, non-plate wearers will end up with more Stamina than before. Health pools will be much closer between plate-wearers and other classes.
What is going to separate the Tanks from the non Tanks? Our armor will not mitigate much more than Cloth and our health pools will be closer. We will have are our stamina scaling talents. Few attacks will do no damage (the ones we dodge), some attacks do less damage to us, (those that we parry, or block), and some attacks do a lot less damage (those that would crit non Tanks). But overall, Tanks and non Tanks are going to be a lot closer in Cataclysm than they are now. We may even be returning to the days in Vanillia when specs like Arms and Ret being able to throw on a Sword and Board and becoming capable offtanks.
As we get later and later into the Cataclysm cycle, and as the differences in damage between Tanks and non Tanks becomes trivial and healable, you’ll start seeing every class under the sun start tanking trivial and farm content, especially near tanks like Hunter Pets (assuming Pet scaling) and Enhancement Shamans. But you could even see Mage Tanks and Rogue Tanks as we get further and further in.
Hit On Diminishing Returns?
Combat ratings - All ratings will be much harder to "cap out" at maximum gear levels. Ratings will be steeper in Cataclysm, and creatures in later tiers of content will be harder to hit or crit, similar to how level-83 mobs are harder to hit or crit than level-80 mobs.
It's not really diminishing returns on Hit, but it works similar in that you will continue to need more Hit as you progress in raids to stay Hit capped. It just allows you to cap each tier until the next one is released. It's a moving Hit cap that varies on what you are fighting. This is critically important for DPS because getting Hit Capped is one of the first goals of a Raiding DPS class. In Cataclysm, you will have to reacquire the Hit Cap each tier because it will be higher in Tier 12 than it was in Tier 11.
This was put in for our DPS friends, but it's really going to nail tanks when it comes to Threat Generation. Hit is the number one Threat stat for Paladins, and it's important for the Threat Generation of the other Tank classes as well. In Wrath it wasn't until late Tier 9 and into Tier 10 that the item budgets on our gear were large enough to afford enough hit rating to cap it in any reasonable set of gear. With Hit effectively on diminishing returns I wonder if Tanks will have enough Hit on their gear to cap each Tier. We may go back to what we told Tanks early on in Wrath: Gear to survive and take whatever amount of Hit you get on that gear and make the best of it.
How will today's gear change in the Cataclysm pre-Patch?
* No more Defense on gear. Existing Defense becomes Dodge, Parry, or Block Rating.
* No more Block Value on gear. Existing Block Value becomes Block Rating.
* You'll have as much Stamina as you're used to, though you may notice your tanking plate has a bit less Stamina than a comparable piece of DPS plate, since we tend to take the gem budget out of your most attractive stat.
* Bonus Armor on gear will go down slightly.
So those Bonus Armor Emblem pieces will get hit and depending on how the distribution from Defense to Dodge/Parry/Block goes something that is worse today could be better tomorrow.
These are some very interesting changes all around. When we switched from Burning Crusade to Wrath, Paladin Tanks were redesigned on nearly every level. We changed from Spell Power to Strength, and got some additional attacks that made us more Warrior-like. Tanks in general were changed as baked in threat was reduced or eliminated and the native threat of our Tank stances was increased (or everyone not in those stances is reduced depending on how you look at it). It was like learning a new class. Now as we look at Cataclysm, all tanks are getting a fairly substantial redesign once again.
We, as the Tanking community of Paladins, Warriors, Death Knights and Druids, will do what we always do. We'll investigate, and learn and master our new class. We will cry over the nerfs, we will whine for buffs (well maybe just the Warriors, j/k!)
At the end of the day, we'll continue to be fantastic tanks in Cataclysm.