Last night, Militiae Templi ventured forth into the lair of the dread Gronn-lord, Gruul the Dragon slayer, and put the beast in his place. Despite our many attempts in recent weeks, we simply could not win the DPS war against this abomination, and though we had learned the mechanics of Shatter and were staying alive, his enrage damage boosts would eventually put him in a position to one shot our tanks before we could extinguish his life.
Apparently we were not alone, so in response to an overwhelming belief that the encounter was far too difficult for all but the most successful Uberguilds, Blizzard retuned the fight and many guilds found success where only failure had wallowed.
Gruul is a long encounter due to his extraordinary amount of hit points. Prior to the nerf, I think he was in the 4-5 million range, though that received a significant reduction during the hotfix this past week. In order to challenge the beast successfully, you will need to understand and master a few important details about this fight.
Gruul enrages periodically which boosts his attack speed and DPS. It was not uncommon to have him hitting for over 8000 damage on the main tank by the end of the fight and our DPS was firing hard. This makes it critically important to avoid unnecessary deaths because if too many of your DPS fall victim to the various periodic damage or your healers die, you will simply not have the gas to take him out before he becomes a tank killer.
Quite frequently, Gruul will knock the ceiling causing a Cave In, which is an AOE damage effect, that can easily be run out of. If you pay attention and move quickly, you will never lose a player to this effect, and if you see someone die, be sure to berate them for lack of situational awareness. You simply can not afford to lose anyone to this effect.
Next is the most difficult ability to learn. Ground Stomp sends every member of your raid flying through the air in a random direction. You must then space out quickly, before the Gronn-Lords Grasp immobilizes you in place, and you Shatter, causing damage to yourself and anyone within 20 yards of your location. If 3-4 people are grouped together, they will all kill each other and you might as well call it a failed attempt. If only 2 people are within range, you should take less than 5000 damage and can fight on.
Gruul also will silence the raid, and we found that this was a frequent time for tank deaths, so be sure to keep HoTs stacked on your main tank and off tank throughout the fight.
Tanking Gruul is a difficult task and requires two tanks with plenty of damage mitigation and tons of health. Your main tank will take nearly all of the attacks, but Gruul will switch to his second highest melee threat every once in a while and Hurtful Strike for 12-15000 damage. If your second highest threat player is not a protection warrior or feral druid, they are surely dead. Our guild has the Hunters cast Misdirection to the two tanks throughout the fight, every time the cool down is up, to boost their threat position against Gruul.
All in all, the fight has become quite manageable and he went down after a few short tries.