Since Sunwell opened, both on the PTR and on Live, I've seen a lot of discussions where Brutallus is referred to as a "bad fight for a Paladin tank." This boggles my mind, especially when the same people will go extra light on healers purely to make up the DPS difference.
The primary reason behind this sentiment is that Paladin tanks will take, on average, 4% more damage than a Warrior tank. This is true; I've got WWS logs that show it. You have to look at the nature of that incoming damage, though.
First of all, tanks don't die by 4% of their health on this fight, provided they have the minimum health required (which is just over 23k, easily attainable for a T6-geared Paladin). No tank can survive two of his attacks (which is two mainhand and two offhand swings) with no heal and no miss/dodge/parry. You're talking about upwards of 30k damage between all four hits (about 15k per), in the span of about a second. Sure, a Warrior with Last Stand up probably could, but you can only do that once per fight, and you've got 5-6 Stomps to worry about. Plus, it's impossible to know when you're going to need to pop it. Either you get a heal inbetween hits or you don't; 4% damage reduction isn't going to make that 30k burst more manageable.
Also, as I've mentioned previously on this blog, Warriors get parried more than Paladins. Reducing the "get a heal or die" window of that 30k burst from 1 second to 0.6 seconds is significantly more dangerous than increasing the already unsurvivable 30k to 31.2k. I'm certainly not saying that Warriors will take more damage, or even that it would "all balance out". I'm saying that the extra damage the Paladin takes doesn't matter in the slightest. A 16k hit is no different than a 15k hit when you've only got 9k hit points.
The second and less frequent (but more viable) argument is that Paladins will have some trouble with the taunting. It's true, a taunt resist can spell disaster for a Paladin tank on this fight. With a 15 second cooldown, and a 10 second window, you're only going to get one chance for your taunt to go off. That said, it's really not hard to reach the 9% +hit required to make your taunts unresistable (and as a side note, to all the Paladins who turned up your nose at items like the Pendant of Titans or Band of the Abyssal Lord because "It's got hit on it" - this fight is your punishment). With our Balance Druid in the raid, I'm at 10% without wearing anything special outside of my normal gear. I've got hit gear in the bank I can use to make up that 2% if needed as well. Plus, as long as the resist doesn't come on the first one or two taunts, you can most likely get away with BoP'ing the other tank. I actually pulled aggro one attempt because I was keeping up my regular rotation for the exta DPS. It's not hard to stay #2 after he's been on you once or twice.
And that brings me to why this fight is not only Paladin tankable, but an excellent place for a Paladin tank. This is a DPS race. Brutallus attacks quickly, does a truckload of damage, and is a demon. Paladin threat is through the roof here. Omen is wildly inaccurate, this is true, but I never saw it go [i]under[/i] 1k, and it spikes up to 3k fairly frequently, even without Wings. No misdirects either, we save those for the Warrior tank. If I had to make an educated guess, I'd say I average somewhere in the 1600-1800 range on this encounter.
He attacks fast enough that Holy Shield charges can actually run out. He does so much damage that not only is mana never an issue, but I can keep up a full threat rotation when he's on the other tank and be topped off the second I taunt him back. Plus, since I get threat from gaining mana via Spiritual Attunement, part of his DPS translates directly into threat for me. DPS doesn't have to hold back - and that's critical on a fight that already comes down to the wire every kill.
We spent a whopping 6 raid hours on Brutallus over a span of 2 days before we killed him. I think it would be hard to make a case that using a Paladin tank makes the fight harder.