When I run heroics...
The team is Prot Paladin, 3x Elemental Shaman, 1x Warlock.

The team gets replenishment from the warlock.
The pally does Blessing of Wisdom on each of the others, Santuary on herself.
I use Runescrolls for Fortitude and Drums for 8% Kings + MotW.
Water Totems are on a click system... 3x Healing, then each of the next 3 clicks drops a Cleansing instead.
Shammies use Water Shield and refresh it often.
And Shammies Thunderstorm towards the end of each fight.
Only the Warlock needs mana, but Lifetap fixes this and there is a ton of passive healing between Fel Armor and 3x Healing Stream.
I've added Endless Mana Potions and Endless Healing Potions (Alchemy) to the mix, on their main Click key.

Not sure if you're doing all this or not.
Hopefully some of it helps a bit.