We found Warlord the hardest fight as well but we are only running with 3 healers and the only time we suffer is in phase 2 where our healers take turns to blow a raid heals cooldown as soon as everyone is stacked.
We set up 2 markers for the ranged and heals in a line and have the boss face the raid until the ball spawns then turn him 90 degrees to avoid the frontal cone attack.
as soon as the ball has enough stacks we move the melee group out of the way allowing the ball to hit the boss.
we usually have 2 heals and 2 melee in melee range.
and rest dps + 1 heals in the ranged group.
Single people shud not be dying in phase 1 unless they are either not stacking properly or the debuff is not being cleansed at the right time.
remember you cant cleanse the debuff if the ball is about to hit the group or that person will most likely die.
p2 is really just about using a raid heal CD as soon as all are stacked and then any self heals etc people can use to help.
as a dps warrior i also help out with rallying cry etc.
what 3 heals are you using and what tank.