
I tank a lot. I moved back into tanking around March or so of this year, because a tank was needed, and I know how to tank. I've stayed a tank in Mists of Pandaria so far because the last thing anyone needs is another melee DPS, because I generally like tanking, and because the new tanking system has actually given me something to learn. What have I learned tanking so far? Well, lots of things, actually. Here's a few highlights.
So let's talk about tanking in Mists of Pandaria.

For starters, and I doubt any long term warrior tanks need to be told this, but five man and raid tanking have diverged fairly significantly from one another. In five mans, I rarely have to spend a lot of time thinking about either my threat or my survival – I spend most of my time wrangling packs of mobs together, and paying attention to the environment to try and make things easier for my healer by not standing in avoidable damage. Tanking a five man at this stage of the expansion is mostly based around that environmental awareness and keeping control of trash packs, and boss tanking in heroics is all about learning what the boss does. So if tanking Siege of Niuzao Temple, for instance, most of the effort of boss tanking lies in realizing what each boss does and adjusting for it. General Pa'valak requires you to be ready to pick up adds, while Wing Leader Ner'onok is a mobility fight. I don't want to say that heroics are overly easy, because I think they're actually tuned fairly well for the gear you're wearing when you start them, but they're much less punitive than the Cataclysm heroics were at this stage in that expansion's life.
The Raiding Life
Raiding, meanwhile, has emphasized tank damage reduction, avoidance, and awareness of incoming avoidable damage while also adding in gimmicks that have to be adjusted to. Whether it's juggling the Stone Guard, using one of the abilities tanks gain (Nullification Barrier, Shroud of Reversal) in the Feng the Accursed fight, or killing the Severer of Souls on Gara'jal you see tanks tasked with things beyond merely staying alive and holding threat. That doesn't mean you're not expected to do those things, but rather that you're expected to do those things and be awake and aware of whatever else the fight asks of you. Frankly, that's probably the best aspect of tanking right now, the increased feeling of situational awareness necessary to performing your job.
Let's face it – tanks have a tendency to assume that tanking is harder than DPSing, and it's not. The tanking role has a lot more pressure than DPSing does, purely because there tends to be less tanks and more attention paid to individual tanks because of it. With threat and Vengeance the way they are now, the only time there's really much of an issue on threat is at the very beginning of a pull when DPS can get overly excited and hit a boss before the tank or get a huge crit streak before the tank has had time to get Vengeance stacked up. This happens, but it's usually the fault of DPS getting a trifle over-excited, and isn't a major concern. Threat isn't getting pulled in phase three of a fight. So giving tanks a mechanic to work, or a condition to juggle, or another task like killing an add is actually fairly interesting as it switches up what the tanking job is, although as a warrior I feel like the Severer of Souls really illustrates how pointlessly low warrior tank DPS is. Frankly, making a part of the fight a tanking DPS check isn't really fair to warriors. I don't like feeling like I should step out for another tank for the good of the raid based purely on my DPS while tanking.
Stat stacking and value
People have asked me a lot if they should stack mastery as a warrior tank. Technically speaking, yes. I don't like to say yes to this, because I know people will immediately start reforging hit and expertise to mastery, especially after I told you that mastery, dodge and parry were all better than hit and expertise. The problem with this is, while we get more survival bang for our buck out of those three stats, in the active mitigation world we can't afford to be the tanks who don't have any hit or expertise. Our damage is already low, we really can't afford to be missing a lot. My advice to you, warrior tanks, is to neither gem for or reforge for hit/expertise nor to treat them like dump stats. If you can get between 3.5% to 5% on both hit and expertise without reforging or gemming for them, you should do so. I'm primarily gemming for mastery or mastery/stamina if I find the socket bonuses compelling, because while mastery is probably our best pure avoidance stat, it doesn't do jack against magic damage, and Shield Barrier does. If you want to use Barrier, you need rage, and we get that either from hit/expertise or from dodge and parry (since those proc Revenge). The other reason Barrier becomes compelling as a fight goes on is how it interacts with the attack power gained through Vengeance.
Shield Block, however, shouldn't be ignored. Boss auto-attack damage and any melee ability makes Block a lot more appealing, it's probably still our number one mitigation ability. The high rage cost is the real issue with Shield Block, which is why I glyph for a larger rage pool to offset the cost.
Right now I'm still on the fence about how I like the tanking redesign. I famously sang the praises of the Cataclysm protection warrior, and I haven't really changed my mind about it. I feel like Shield Block is too costly for its benefits and that it needs to come down in rage cost or go up in duration (either extend the block buff from it to 8 seconds, or drop the rage cost 10 or 20 points in my opinion) to make it more useful in five mans. Yes, that means I don't think our tier 14 set bonus goes far enough. In raids and challenge mode dungeons I know its use goes up. So far I'm happy with encounter design in Mists of Pandaria, it reminds me of the best of Cataclysm Tier 11 mixed with the best of Tier 13. I'm loving Storm Bolt for my tanking spec, especially on bosses that can't be stunned as it's a ridiculously strong pull and adds significant damage to my otherwise weak output.
Next week, barring any significant changes I'm going to be looking at rep gear by faction.
More at The Care and Feeding of Warriors: Tanking in Mists of Pandaria