My guild is currently progressing on H Megaera 10 and we are having difficulties getting to the last few rampages. I am not sure which area needs to be improved (DPS? Mechanics? CD management? Raid Positioning?). We are using a strategy with one tank on the heads and the other on the adds for interrupting and stuns. Someone seems to die generally to ice beams and there is occasionally some bad ice placement. We have healers stand just in range to heal the tanks and ranged DPS stands at max range.
You need to add your holy paladins wings and guardians CD into that rotation as well and make sure both paladins are using lights hammer during every rampage and not just stacking them on the start of it make sure they chain them so you have constant healing throughout the rampage instead of just burst healing at the start and nothing for the last half of it.
Really with a dps shaman doing that much healing you should be able to heal rampage 4 with holy pally wings and no other raid CDs besides spirit shell and 2 paladin lights hammers.
you need to hold lust for the last head or the 2nd to last. DPS should use dps cds on the 2nd red head.
We got our first kill with Hero on #4 but we were also having the "problem" that heads were dying too fast so that 3 min CDs weren't up for the 4th, 5th, and 6th Rampages so we loaded up our big CDs on 1+5 and 2+6 then we had just a few CDs on 3 (Smoke/Devo/Personals) and just ToL/Hero on 4. This was mostly caused by having a Warrior DPS tank the adds.
Druid should make it a priority to plant shrooms at the next stack point after each Rampage ends so they're fully charged for the next Rampage. Shrooms can do over 1.5 million healing every Rampage. Swiftmend should be used twice as often. Nature's Vigil was only used once when it could have been used thrice. Glyph of Wild Growth is a better glyph than the completely useless Glyph of Rejuv even in 10-man, especially for this fight. Nourish should never be cast -- ever. Even the Heroic upgraded Spirit of the Sun is worse than the Upgraded Valor Trinket. If they've never picked up the Valor trinket that's... unfortunate.
I'm not exactly sure how you have so many deaths from Ice. Run straight back with Ice. Healers need to have faith in the other healers to keep the tank up. Icy ground slowly expands so don't let it slowly expand onto where you're standing.
Also, not to scare you off Megaera, but I feel Primordius and Twin Consorts are both easier Heroics for 10-man -- there's certainly less going on during them.