I agree with you, but unfortunately, numbers talk.
I have almost the same problem as a tank. People pick tanks with higher HPs over the ones with lower HPs even though there is absolutely no basis for it. Smart tanks gem for avoidance with some sta, the dumb ones gem all 60 stas and gain over 200k HP with shitacular avoidance and become mana sponges for the healers, yet they will be picked over the smarter tanks who gem balanced because their higher HP makes them appear better geared -_-.
Sucks, when I get into a random and the healer QQs that I only have 160k HP. Yet neglects my superior 12% dodge, 15% parry, and 50% block rating.
People put too much emphasis on numbers in this game, and unfortunately, there is nothing you can do about it. Druids ARE healing more than any other healers and thus GMs will want more of them healing, regardless of whether half of that are overheals.