The tough thing to me is figuring out how to AoE heal in 5 mans. Healing 2 people plus myself is pretty easy. When the whole party loses over half their life in an instant it gets rough. The only way to do it seems to be to predict when the aoe damage will come and be ready with 3 HoPo, standing in the right place to LoD/HR. Otherwise I have to use FL or let people die. So I struggle to determine when it's safe to use HoPo for WoG (increasing mana efficiency) and when I must save it for Light of Dawn (increasing throughput). It almost seems to depend on how good the dps are at avoiding damage.

Michael, you are exactly right. That is exactly how it is supposed to work in Cataclysm. If a healer goes oom, it's not always because the healer was inefficient. It's equally true that people were taking damage they shouldn't. Predicting AoE damage is also a definite must, and even if you can't always know exactly when it will happen, constantly be on the lookout and shift your position to be able to throw out LoD immediately and hit as many as possible. If you're in position before the damage goes out, you don't have to waste time running to orient yourself or mana using FoL.

If people are taking avoidable damage, let them die, Michael. Nothing tells a DPS that they should be paying attention to what they do and where they stand like falling face-first into the ground.

"The tough thing to me is figuring out how to AoE heal in 5 mans."

It seems everyone is forgetting Holy Radiance for some reason. It is our AOE heal, so it makes sense to use it to AOE heal in 5 mans. It's incredibly helpful and on a fairly short timer considering. It's a bit costly, but on rough pulls I can usually use it more than once and still spam my other heals in the process without going OOM.