Your gemming and enchanting are pretty much flawless, and I think you know there are some gear upgrades you can get (like Pillars of Might and the frost emblem cloak) but frankly you're in decent shape for the 1st bosses of ICC.
Do you have any combat logs to give us a better of idea of what's happening? If your healers are wroth their salt you could probably stand in the fire and get saber lashed and still survive for a little bit. Something doesn't seem right to me. The only other thing I can say is what they've already said. Make sure you're dancing in and out of the fire properly, coordinate with your other tank where you are going to go (so like when the first fire hits move right, then left, then right, etc.) so that you don't accidentally put the cleave all on one tank.
For Lady Dreamwalker: The adds don't hit very hard except for the deformed guys, they can't be tanked so if you're not surviving them it's because you're not supposed to. They need to be kited away, they move really slow and this is very possible. Either have a dps like a warrior or ret pally or something ranged taunt them away, hunters with distracting shot can work well too. The only other really hard hitting thing about LDW is her frostbolts. They are interruptable so make sure that you have an interrupt rotation. Two people can do it easily, if you need to, call it out on vent "I have next, you have next, I have next," etc.
Gunship: This is really on how fast your DPS can react if you're tanking the horde ship. If you're tanking your ship and are just tanking adds, survivability really shouldn't be an issue. If you're on the horde ship, getting back as fast as you can after the sorcerer has died is really all there is to it, it's a pretty easy fight.
Deathbringer Saurfang: This is pretty much just a tank and spank. Just as long as you are taunting off of your other tank when they get the blood rune or whatever it's called and you don't pull aggro on the adds you should be fine.
In general: try to be proactive about your cooldowns. If you think you're about to take more damage, hit IBF, or UA, or whatever you think will allow you to survive, even trinkets timed well can be very beneficial even if they are smaller cooldowns.
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