Really, this comes down to what a druid is (aside from a wildhsaping, animal summoning combat god), which then reaches into setting as much as it does mechanics and D&D-isms. I like to use the druid to represent the priests of the barbarian/savage/uncivilized peoples (regardless of race), not necessarily as specifically nature priests. For nature priests, you have clerics that have access to the Animal and Plant domains, that do the bidding of their dieties -- which might ver well, depending on the deity, include admonishing villagers for overusing resources, or burning said villages to the ground. Even then it isn't so much an issue of conservationism as it is committing to the will of your deity. Since druids need gods even less than clerics, though, I tend to see them as priestly on in the sense that they might impart wisdom and structure on their community. It is a blurry distinction in the real owrld, but in a world where gods walk, it is a very definite one.