Spamming AoE heals when only the tank is taking damage is one of my biggest healer pet peeves. It is one of the few things that I will actually call players out on. Fortunately, it doesn't happen that much. In DF though, I take what I get, and only mention anything if something someone is doing is screwing up the run, or to discuss things after a wipe.

I always assume a tank who remains in defensive stance is feeling things out. I really don't care about his/her DPS output. Not in a PUG anyway. And I actually appreciate tanks who gets a feel for their group, especially their healer before kicking it into high gear.