Blood tanking stat priorities
Stamina In the Wrath era, stamina was more than the king of stats -- it was the lord high emperor. In Cataclysm, things are different. You can consider stamina something of the viscount. It's still a very important stat, and you definitely want to have a high health pool, but you don't need to focus on it to the exclusion of all else. Cataclysm health pools are set up to be incredibly high, and Cataclysm bosses mostly avoid high-damage attack gimmicks, so you can generally have a lower health pool and stay partially healed for longer without dying (assuming you juggle your tanking cooldowns well, of course). With that in mind, don't go too much out of your way for stamina anymore, and don't be afraid to regem for mastery or avoidance if you need more of them.
Mastery Mastery is an incredibly nice stat for death knight tanks, as it feeds into Blood Shield. For the most part, you'll want to reforge for mastery wherever you can. The larger your blood shields, the longer you survive.
Parry and dodge ratings While you can get a small amount of parry rating from strength, most of it will come directly from the stat's appearing on your gear. Unlike in previous expansions, parry and dodge rating are actually essentially equal in diminishing returns, so you should aim for equal amounts. Don't be afraid of their being slightly unequal, but where you can, gear, reforge, and regem to keep them relatively equal. It's worth noting that avoidance is still heavily reliant on the RNG, so you can still get incredibly unlucky from a bad streak of failures. Still, between Blood Shield and your health, you should be able to weather it.
The exact amount of parry and dodge rating you should have is still under strong debate in the death knight community. The current strategy for most death knight tanks is to get your avoidance to some arbitrary amount (generally somewhere around 15% for heroics and 30% for raids), and stack mastery above and beyond that. Another option is maintain two sets of armor, one that focuses on mastery and another that focuses on avoidance. This, of course, will take time and many drops, so it's not feasible for everyone.
In the end, the best way to choose between mastery and avoidance may be to take a look at your playstyle. If you like having more direct control over your survivability, pump up your mastery and use Blood Shield. If you prefer to let the system take care of it whenever possible, pump up avoidance and hope the random number generator favors you.
Hit rating Hit rating is now arguably a survival stat, as Blood Shield will not be activated if your Death Strike misses. You'll need 8% hit to assure that doesn't happen. That said, chances are you'll just hit it on the next GCD, so unless you're consistently dying over the course of one GCD, you probably don't need to obsess about hit rating. Just let hit rating come when it does, and maybe consider not reforging it away.
Expertise rating With the demise of parry haste, expertise has lost a lot of ground in the tank stat race, being demoted from a defensive stat to a pure threat stat. It can still provide some extra threat, but for the most part, the general consensus for it is the same as it is for hit rating. Don't struggle to hit the 26 expertise soft cap, but if you get some gear with expertise on it, consider it a bonus. Akirus the Worm-Breaker is a great death knight tank weapon for this very reason.
Armor Armor is still an incredibly useful stat that allows you to mitigate massive amounts of physical damage. You'll probably come across as much armor as you need just by equipping tank gear, though, as extra armor on gear is mostly gone as an itemization gimmick in Cataclysm.
Strength Strength is a threat stat, even a very minor survival stat, thanks to the existence of Forceful Deflection. That said, it's never something you should actively seek. Let it come to you on tank gear, and it should be more than enough.
A typical PvE blood tank build
This build is a very typical PvE raid tanking build for a blood death knight. It incorporates frost as a secondary tree in order to take advantage of the Lichborne/Death Coil healing trick. You'll notice the conspicuous absence of Abomination's Might and Crimson Scourge. While both talents have their uses, they simply don't contribute the raid tank's main jobs of boss tanking and threat or survivability. If you feel like you want some extra AoE threat power or need to provide the attack power buff to your group or raid, the best way to redistribute points is to take one point out of Epidemic and one point out of Scent of Blood. Other options for spending those two "extra" points include Endless Winter, which can be very useful for a tank who needs to double on interrupt duty.
The linked build also contains some recommended glyphs. Don't be fooled by Glyph of Death Strike. It only increases the damage of Death Strike, not the healing (which is now disconnected completely from Death Strike's damage), so it's not that great for tanking. One thing you may wish to consider is to swap out Glyph of Death and Decay for Glyph of Death Coil. With the recent nerf to Glyph of Death's Embrace, the Glyph of Death Coil can provide a much needed boost to the Lichborne trick's healing power.
Rotations and rune usage
Like the DPS specs, blood tanking doesn't so much have a rotation as it does a priority, since Runic Empowerment can provide new runs at any moment. Make sure you're in Blood Presence at all times, as you'll really want the extra defense, threat, and that extra rune refresh speed from Improved Blood Presence.
First, always make sure you have your diseases up, at least on bosses. Blood Plague provides the Scarlet Fever damage debuff, and Frost Fever provides an attack speed debuff. Both directly contribute to your survivability in a relatively major way. Diseaseless tanking may still work on weaker trash, but for the most part, those debuffs are too important to lose now. After that, your priorities will fall to strikes in order of effectiveness and utility.
Rune Strike remains our most powerful threat producer. Use it whenever you have the runic power to do so unless you're saving it for an immediate use of Lichborne healing.
Death Strike is a key cornerstone to any rotation, providing both threat and survivability via Blood Shield. Also, since Blood Shields now stack, you don't have to worry about timing your Death Strikes. Just churn them out as you have the runes.
Heart Strike will be used if only to keep your blood runes on cooldown. Otherwise, you'll probably end up using Death Strike for the survivability.
For an AoE damage priority system, you'll definitely want to keep Death and Decay
up. You'll also want to use Outbreak
to get diseases spread if needed. Other than, tab target with Rune Strike and Death Strike for survivability, and use Blood Boil
for more than three mobs, Heart Strike for two to three mobs.
When you need to use a tanking cooldown, use your priority system to get your threat rotation focused. You can use Blood Tap
for minimal disruption, of course.
This covers the very basics of what you need to know to gear and play your death knight tank. Next week, we'll focus on gemming, enchanting, and reforging strategies for the blood death knight tank.
Learn the ropes of endgame play with WoW Insider's DK 101 guide. Make yourself invaluable to your raid group with Mind Freeze and other interrupts, gear up with pre-heroic DPS gear or pre-heroic tank gear, and plot your path to tier 11/valor point DPS gear.