One of the overlooked idiosyncrasies that OD&D originated (and that AD&D maintained) is the notion that clerics could be any alignment but Neutral. In OD&D, this meant a choice between Lawful and Chaotic, with Chaotic clerics being in fact "anti-clerics" whose spells were in many cases reversed versions of their Lawful opposite numbers. When Eldritch Wizardry introduced the druid as a playable class (a "monster" version of them appeared previously in Greyhawk), we finally had a Neutral "cleric," complete with his own selection of unique spells.
Now, I like the druid and I find, particularly in a setting where Law and Chaos play an important role, the idea of a Neutral religious class is particularly appealing. In later AD&D, druids came to be more explicitly associated with the elements and elemental planes and I think this is an intriguing idea. I'm now toying with the notion that there are no gods associated with "natural" things, like the weather, the seasons, the oceans, fertility, etc. I'm even considering the possibility of having no god associated with death. Those things either have no divine patrons or else are associated with various elemental lords. The druids, in this scheme, would be mediators between the world of mortals and the greatly-expanded-in-conception natural world.
Foolish consistency may be the hobgoblin of new school game design, but I think any version of the druid I create would be based more closely on the mechanics of the cleric, with some new abilities and, of course, spells swapped in to compensate for their loss of clerical staples like metal armor and turning undead. Eldritch Wizardry gives lots of food for thought here, as does Greyhawk, which calls druids "combination clerics/magic-users." I rather like that, given how the way I wish to tie clerics and magic-users more closely together conceptually. Still, I have to think on this some more. I've got the germ of some good ideas, but they're still pretty rough.
Once I've worked it all out in my head, I'll post my Swords & Wizardry-based version of the druid here.