Glakras Heroic Drakefire.

[Deleted]

We send a balance druid, BM hunter and a frost mage up there, together with a warrior tank and discipline priest. The miniboss dies in 10 seconds, and then the tank and disc priest go down again, while the 3 DPS get rid of the adds there. Ground group is a resto shaman, enhancement shaman, frost mage, destro warlock, paladin tank. We don't have any issues with the drakefire at all.

[Zerah]

Our group had issues with the large amount of damage from drakefire. It easily is the most raid damage going out at any point in the fight.
We 2 heal, disc priest + resto druid or mistweaver.
We send 8 up the first tower, leaving the disc priest and prot warrior down to deal with adds.
Our tank uses personals to stay alive, and our priest usually ends up pain suppressions himself.
We also allow the grunt to kill the first engineer team, as a new one will spawn after. We mark the grunt at the 2nd tower before heading up to the first so we can blow it up as soon as we get down. The mini boss on tower one usually dies before his first arching smash, with our healer going down after he dies.
It should be noted that allowing the first demo team to die means we get an extra add wave before dropping gala. This group has two shammies so keeping them stun / interrupted is key. Also make sure to kill the healing tide totems, as two drop at the same time

[Whitehall]

The way my group mitigated this is by keep both healers on the ground and sending our ele shaman up. He can easily keep the tower group up with ancestral guidance and healing tide. I don't see why this wouldn't work with an enh. This lets us keep both healers on the ground dealing with the hellish drakefire. It's worth noting that this will only really work if the tank also has strong self heals.

[Moller]

There are a few options for handling that part of the fight. Drakefire is a lot of damage and it increases so the more people you leave down and the longer it takes the tower group to start shooting down the drakes the harder it becomes.

Option 1 is to send a usual tower comp (1 tank, 1 healer, 2-3 dps) and have the healer below save all cd's for the drakefire (avoid any temptation to use them on the poison miniboss). As soon as the tower miniboss dies the tower healer comes back to help.
Option 2 is to keep both healers on the ground and send a hybrid with good healing cd's with the tower (may also require a self healing tank, depending on gear).
Option 3 is to send the majority of the raid into the tower. Typically on 10 man you might leave a tank and healer behind and just plow through the tower quickly.

All 3 options work and I'm sure there are many other variations that will also work. My feeling is that option 3 is probably the safest if your group is not accustomed to any particular strategy.

[Deleted]

Since that is really the only hard part of the fight - we just send 8 up the tower (1 tank, 1 healer, every DPS) and leave another tank with one healer below to just sit with the adds and keep them from killing the NPC's, basically. The tower adds get absolutely blown up and the drakes are down before they get barely any stacks. It just makes the fight so much easier.

For the second tower we leave one melee DPS with good stuns down (monk or DK with grip) since there's a bonecrusher up at that time and we don't want him killing an NPC due to a missed tank stun or something.