I just did this with my recently turned 70 shamans, was pretty easy (skipped 2nd boss). My shamans have 500 spell damage or so (lol), just 1 piece of epic gear - the s2 weapons so far is all I've gotten. Some more tips, in additions to the ones above:

- I found it very helpful to have one of my shamans be resto. in place of lightning bolt, I put healing wave rank 8 (cast on tank), so he was always healing the tank while others were spamming DPS. I use a prot pally, 15k hp unbuffed. earth shield is very nice too, I always kept it up.

- kill netherbinders first, then healers, then melee

- for demon packs, just kill the big guys first while pally aoe tanks the little guys. my rotation would be all cast lightning bolt, then all cast healing wave r10 on pally. he did drop quite low a number of times, but I didn't die on any of them and I killed every single mob in the instance except 2nd boss (didn't even try her, doesn't drop any loot I want and she sucks)

- for first boss (capacitus), you can line up all your shamans around the west side stairs and near the elevators, spread them all apart. i put my healer on the back part of the stairs in the middle. my pally pulls capa and tanks him sitting in the middle ledge of the stairs, he gets hit by very few bombs this way. None of the shamans got hit by a single bomb. He does have a huge HP pool, and since the shamans are so spread out they don't get anyone elses totems, I should have dropped mana totems for all of them. Still wasn't too hard, just the last 10% took forever since everyone was oom (i used 2 of the "tk only" mana potions on the healer).

- as I mention above, you can reset gauntlet every wave. I did this, and after last wave before boss (he did MC and summon one of my shamans, and instantly killed him, only death in heroic).

- for boss I just popped all my fire elementals and went to town on him, chaining heroism. He went down pretty fast, he MC'd a couple ppl but it didn't last long and a few chain heals took care of it.

I found it very easy, a lot easier than I thought it would be. A prot pally + 1 resto spec'd shaman really made it quick, I'm going to try and run this instance daily until at least the shammys are exalted.