Topic Time to thicken your skin.
5 mans aren't that hard. When heroics were first launched on beta, they were pretty challenging, but after they were tuned appropriately and people learned the fights, they just aren't that hard. You'll run into stupid of course as you always will in LFD, but after the initial learning curve, it won't be all that notably terrible.
Why worry about complaining bads? Just do what I've been doing since pre-bc:
If they stand in the fire, STOP HEALING THEM.
If they pull threat because they don't assist the tank for a primary target, STOP HEALING THEM.
If they're eating frontal-cone damage from a boss, STOP HEALING THEM.
I don't care if I'm standing there at full mana. If you're taking damage that can be easily avoided and making no effort to get out of it, you're not getting a heal.
Even the lowliest terribad pub will learn after he eats the floor for the second or third time.