Ugg, I can see where your moonkins would see a bigger drop in DPS than I would. I have yet to take on any content in moonkin form, I do not even have the improved aura speced.... So in a normal cycle say 21 seconds with my above macro set, in full healing mode they will cast 4 instant HOT's per cycle. 3 on the tank and 1 on themselves. Remove haste from the equation and that comes to 6 seconds of global cool downs that your not dps'ing or a good 25%+ of your DPSing time. Also for you, you loose out on the 5% crit and SPI to SpellPower buff from moonkin aura. Thats a lot of dps. (if your normal moonkin lost a lot of dps, how much dps did your tree who now is dpsing add? You may not have lost as much as you think overall)

Prolly what I need to do and may help you as well, is if you dont need 4 caster form healers, Moonkin up the ones that do not need to heal and get the aura/spi buff back. Or use your current setup and when you come across a boss where this works well, Just Shift-Up-Arrow to a different hotbar that has quad caster healing setup.

My setup is grossly innefficiant as well. At the end of instances they have overhealed sometimes in the 200-300k range or about 30-40%. Some heroics I have tried to not use all 4 healing, but right now I dont have the gear and mitigation to survive with out so most of that overhealing is from the end of fights where everything is dead and the next 8 seconds your full HP's and all the HOT's are still going and 4 blooms go off for a ton of overhealing. I use innervate on almost every boss fight because of this where in the past healing manualy I didn't even have that spell macroed up. I am also only useing 2 diff heal spells for all my heal needs and the druid has an arsenal of healing. So yea, fights are going to take longer, I have to drink more often than I really like, but ive also taken on some stuff that I prolly wasnt ready for with my l74-76 quest gear.

What its really good for though is keeping my group alive w/o any micro management of heals, targeting, or DPS.