I don't really like the current description of the Primal Powersource so I'm ignoring it. Druids in my setting have a religious function, although with spirits and elements rather then Gods. And as I'll explain later the typical DnD Cleric is quite impossible in Druidic society.
I shall attempt to explain Druidic society in my game as an example.
Well, this makes it a much more specific question than it seemed to be from the start of the thread, but that's cool.
I think that in terms of the conception of Druidic society you would get just from familiarity with the game Shamans or Clerics would be pretty well an assumed inclusion.
Partially because of Elvish influence the most common Heroes to come from Druidic society in my game are Warlords, Druids, Rangers, Wardens and Fighters. If Druidic society would need to defend itself or form a raiding party said warband would be heavily influenced by these kind of classes (while obviously not all PC's, they would be the equivelent in NPC or Monsters). This would be handy if they were fighting with or against a group of PCs. And I like my setting to have internal coherency.
From this description I think Warlords are really we're you're going to have to go for healing. If you need it to be supernatural - as you explain elsewhere - than I think you should either say that Warlords in this scheme have some access to supernatural healing or just say that people use rituals on top of mundane healing efforts.
Are bards out for this society, too? Because that would solve your problem and seem to fit the theme.
In my game the Druidic society was started by Elves and later on copied by humans who decided that these Elves might be on to something (of course with some differences). However neither the Elves or the Eladrin in my setting believe in Gods. The concept of religion simply does not exist in the Elven psyche.
Druidic human societies instead revere and try and live in some sort of harmony with spirits representing certain things like Cats, Trees etc (borrowing the concept from the Elric mythos).
And how are Shamans different in your setting? Because this seems really really appropriate to Shamans. Almost more appropriate than to Druids.
So I'm interested to see what you are doing with Shamans since from my reading of the classes I'd almost reverse their positions in terms of what you are saying here.
However this still leaves me in a pickle. Since setting wise they have no healers. And when my PC party goes through a Druidic society I would like to see that they have SOME access to SOME sort of supernatural healing. The simplest way to solve this is to either use some kind of Leader class (fluffed to fit) since this also means that if a party with a Druidic theme wanted supernatural healing they could get it.
Warlords are not an option for this. While I can swallow their healing ability used in an adventuring party as the person only having a flesh wound, the same would not work as the main healer in a society. for immersion reasons if nothing else.
If this is really how you feel about this, then - aside from Bard - I think there's a simple way to go about this.
Create an NPC sub-type for this society that does supernatural healing. Unlike the supernatural healers in other societies it never developed into something that could go out and adventure as a discipline.
You already have Warlords and Druids with rituals who can provide adequate healing 'in the field' so if you need something that fits into the society 'at home' you have no need to make it mappable to an adventuring class.
Just create an NPC type that does supernatural healing and then maybe a paragon path that gives some of those abilities to PCs from Druidic societies who want to pursue that path.
Borrow from 2e and call it Hierophants and you've both crafted an easy elegant solution and put in a nice shout out to Druid's Past.