Heya,
My guild defeated this encounter a few weeks ago, so I figure it can't hurt to comment on what strats we used for the fight and how we handled it.
First of all, the basics of the encounter:
Burning Adrenaline (BA) - You probably know how this works, but I guess it doesn't hurt to regurgitate it here. Basically, every 15 seconds a random mana user gets hit by BA, and every 45 seconds the person at the top of Vael's aggro list gets hit by BA. The person inflicted by BA gets all his damage increased by 100% and his abilities become instant cast, but after 15 seconds he dies and explodes. It is extremely important to note that you only explode after the 15 second timer expires. If you get killed by Vael before the 15 seconds go through, you won't explode.
Essence of the Red - 3 minute "debuff" that Vael casts on your raid. It essentially gives your rogues infinite energy, your mana users infinite mana, and your warriors infinite rage.
Chain Cleave - Vael's cleave attack works like a chain lighting (it jumps from player to player till it cannot jump anymore, like the cleave attack used by the Lava Reavers in Molten Core). Due to this, you need to make sure there is enough distance between the current MT and the melee DPS and offtanks to avoid any risks of a chain cleave. An accidental chain cleave on the melee DPS (which can potentially spread to the ranged DPS and healer camp) is probably enough to end the attempt prematurely.
Fire Breath - Standard fire breath attack, no one but the current MT should get hit by this.
With his abilities out of the way, there's 3 prerequisites that your raid group must meet if you really want to see Vael's head on a pike. Those are: 1) proper fire resistance, 2) proper tank transitions, and 3) good, controlled DPS.
Fire Resistance - Every single person in your raid group must have a minimun of 150 fire resistance unbuffed. This is extremely easy to accomplish, since your raid group should have by now some Tier 1 equipment with FR from MC, and you can fill up the rest with crafted items (the wizardweave and volcanic lines of cheap FR gear come to mind). Remember to tell the mana classes to gimp their mana pool as much as possible and go with all the FR (and stamina) they can possibly get. Heck, have your hunters/rogues/druids wear some Wizardweave if needed, just make sure you have the FR. Use the /raresist check built into CTRaid to see if your raid group meets the correct FR requirements. If they don't meet it, don't even try. Also, the four warriors that will be tanking Vael should be at some 250+ FR unbuffed.
Tank Transitions - As you know by now, having the target that is highest on Vael's aggro list get hit by BA every 45 seconds essentially means you need 4 warriors for this fight (if Vael is not dead by the time the four warrior dies due to BA, then you need more DPS because the Essence of the Red debuff will have expired by then). Probably the easiest way to do this is to make sure all warriors have the same spec, and have them run in one after the other with a 5 second interval and start sundering and spamming their aggro generating moves.
As soon as the current MT gets hit by BA, have the next MT in line move to the front where MT1 is, careful not to get cleaved in the way to the front (possibly resulting in the cleave chaining to the rest of the melee DPS). At this point, continue healing the MT with BA for a couple more seconds so he can dish out as much damage as he can, and then let him get killed by Vael before BA expires. Remember, you only explode if the 15 seconds on BA run its course, not if you get killed by Vael before that.
Now, I play horde, and the main tank transitions wouldn't go smoothly 100% of the time (that is, the tank that was supposed to get the aggro wouldn't get it, or a DPS'r would get it instead). The 1.9 patch introduced the Tranquil Air totem though and it makes it hell of a lot easier to make sure the tanks stay at the top of the aggro list. If you play alliance, make full use of that Pally aura that reduces threat on all the melee DPS classes.
I think you mentioned it up there, but what truly makes or bearks this fight is the tank transitions. As long as they go smoothly, Vael will deffinitively go down.
DPS - DPS needs to be pretty good since Vael has to be down before the fourth tank dies. For this particular fight, rogues with the aggro reduction aura spamming feint and vanishing after the 1st MT transition are the best possible source of DPS you can get. Same deal with warriors, since Vael starts off at 20% he will get into execute range real fast, but you gotta make sure they won't pull aggro. If anything, you should soulstone your rogues since they are the only class that can do anything in this fight after losing the Essence of the Red debuff. If your rogues/hunters keep spamming their aggro reduction skills and mages/warlocks are specced for aggro reduction (master demonologist, arcane subtlety), they won't ever pull aggro. If one of them gets BA, they should go to the little corridor leading to the stairs and do as much DPS on Vael before they blow up (frostbolt, aim shot, shadowbolt spam).
With those key points out of the way, there's the issue of healing. A single priest (or even a single Shaman in the case of horde) can keep up his group alive just fine by spamming Prayer of Healing when needed, provided his group meets the FR standards. If your priests are specced into subtlety, it's a pretty good idea to have them Flash the current MT in between casts of prayer of healing. Aggro shouldn't really be an issue since priests won't need to be desperatly spamming heals on their groups due to them having good FR. On top of this, there should be some 4 or 5 healers assigned to the current MT at all times. If some of those assigned healers get hit by BA, the raid leader should assign replacements on the fly.
Once again, the fight is not really THAT difficult. If DPS is steady and FR standards are met, the only thing that can possibly wipe your group is a bad MT transition.
My guild defeated this encounter a few weeks ago, so I figure it can't hurt to comment on what strats we used for the fight and how we handled it.
First of all, the basics of the encounter:
Burning Adrenaline (BA) - You probably know how this works, but I guess it doesn't hurt to regurgitate it here. Basically, every 15 seconds a random mana user gets hit by BA, and every 45 seconds the person at the top of Vael's aggro list gets hit by BA. The person inflicted by BA gets all his damage increased by 100% and his abilities become instant cast, but after 15 seconds he dies and explodes. It is extremely important to note that you only explode after the 15 second timer expires. If you get killed by Vael before the 15 seconds go through, you won't explode.
Essence of the Red - 3 minute "debuff" that Vael casts on your raid. It essentially gives your rogues infinite energy, your mana users infinite mana, and your warriors infinite rage.
Chain Cleave - Vael's cleave attack works like a chain lighting (it jumps from player to player till it cannot jump anymore, like the cleave attack used by the Lava Reavers in Molten Core). Due to this, you need to make sure there is enough distance between the current MT and the melee DPS and offtanks to avoid any risks of a chain cleave. An accidental chain cleave on the melee DPS (which can potentially spread to the ranged DPS and healer camp) is probably enough to end the attempt prematurely.
Fire Breath - Standard fire breath attack, no one but the current MT should get hit by this.
With his abilities out of the way, there's 3 prerequisites that your raid group must meet if you really want to see Vael's head on a pike. Those are: 1) proper fire resistance, 2) proper tank transitions, and 3) good, controlled DPS.
Fire Resistance - Every single person in your raid group must have a minimun of 150 fire resistance unbuffed. This is extremely easy to accomplish, since your raid group should have by now some Tier 1 equipment with FR from MC, and you can fill up the rest with crafted items (the wizardweave and volcanic lines of cheap FR gear come to mind). Remember to tell the mana classes to gimp their mana pool as much as possible and go with all the FR (and stamina) they can possibly get. Heck, have your hunters/rogues/druids wear some Wizardweave if needed, just make sure you have the FR. Use the /raresist check built into CTRaid to see if your raid group meets the correct FR requirements. If they don't meet it, don't even try. Also, the four warriors that will be tanking Vael should be at some 250+ FR unbuffed.
Tank Transitions - As you know by now, having the target that is highest on Vael's aggro list get hit by BA every 45 seconds essentially means you need 4 warriors for this fight (if Vael is not dead by the time the four warrior dies due to BA, then you need more DPS because the Essence of the Red debuff will have expired by then). Probably the easiest way to do this is to make sure all warriors have the same spec, and have them run in one after the other with a 5 second interval and start sundering and spamming their aggro generating moves.
As soon as the current MT gets hit by BA, have the next MT in line move to the front where MT1 is, careful not to get cleaved in the way to the front (possibly resulting in the cleave chaining to the rest of the melee DPS). At this point, continue healing the MT with BA for a couple more seconds so he can dish out as much damage as he can, and then let him get killed by Vael before BA expires. Remember, you only explode if the 15 seconds on BA run its course, not if you get killed by Vael before that.
Now, I play horde, and the main tank transitions wouldn't go smoothly 100% of the time (that is, the tank that was supposed to get the aggro wouldn't get it, or a DPS'r would get it instead). The 1.9 patch introduced the Tranquil Air totem though and it makes it hell of a lot easier to make sure the tanks stay at the top of the aggro list. If you play alliance, make full use of that Pally aura that reduces threat on all the melee DPS classes.
I think you mentioned it up there, but what truly makes or bearks this fight is the tank transitions. As long as they go smoothly, Vael will deffinitively go down.
DPS - DPS needs to be pretty good since Vael has to be down before the fourth tank dies. For this particular fight, rogues with the aggro reduction aura spamming feint and vanishing after the 1st MT transition are the best possible source of DPS you can get. Same deal with warriors, since Vael starts off at 20% he will get into execute range real fast, but you gotta make sure they won't pull aggro. If anything, you should soulstone your rogues since they are the only class that can do anything in this fight after losing the Essence of the Red debuff. If your rogues/hunters keep spamming their aggro reduction skills and mages/warlocks are specced for aggro reduction (master demonologist, arcane subtlety), they won't ever pull aggro. If one of them gets BA, they should go to the little corridor leading to the stairs and do as much DPS on Vael before they blow up (frostbolt, aim shot, shadowbolt spam).
With those key points out of the way, there's the issue of healing. A single priest (or even a single Shaman in the case of horde) can keep up his group alive just fine by spamming Prayer of Healing when needed, provided his group meets the FR standards. If your priests are specced into subtlety, it's a pretty good idea to have them Flash the current MT in between casts of prayer of healing. Aggro shouldn't really be an issue since priests won't need to be desperatly spamming heals on their groups due to them having good FR. On top of this, there should be some 4 or 5 healers assigned to the current MT at all times. If some of those assigned healers get hit by BA, the raid leader should assign replacements on the fly.
Once again, the fight is not really THAT difficult. If DPS is steady and FR standards are met, the only thing that can possibly wipe your group is a bad MT transition.
The gods made heavy metal and they saw that is was good
They said to play it louder than Hell
We promised that we would
When losers say it's over with you know that it's a lie
The gods made heavy metal and it's never gonna die
- Manowar
They said to play it louder than Hell
We promised that we would
When losers say it's over with you know that it's a lie
The gods made heavy metal and it's never gonna die
- Manowar