The Greenbond and Spirit Shaman are nice classes, IMHO. Also look at the Totemist, the OA Shaman, and, believe it or not, the Binder.
Some non-exclusive ideas:
The SS has one feature that I like that is underrepresented in D&D- its a class centered around an animistic worldview. They derive their power from working with the spirits that inhabit the world around us. Take the SS and boost its link to the spirit world, let them converse with them, learn from them, gain power from working with them.
Another possibility would be someone who can self-buff based on his totemic animals. A totemic character might also be able to take on animalistic abilities- akin to what happens with Eberron Shifters.
Perhaps like in Michael Moorcock's Eternal Champion story arc, he derives power from pacts with nature deities. (This would be best modeled by something like the Binder.)
You could have them choose Domains, like a Cleric, but limited to the various nature-themed ones. In addition, as they level up, give them characteristics based on those domains akin to the Drift mechanic of the Geomancer.
Equip the class with a bonus and slightly broadened variation of the "Elemental Substitution" feat. In addition to the usual, add appropriately themed nature sources. Example: Flaming Sphere- a direct-damage area-effect spell- could be modified to do "plant" damage. How does this work? Like this: someone within the sphere of effect is attacked by woody plant roots intruding into the skin, or plants that they consumed blooming and growing painfully within their digestive tracts, or the like (see issues of DC Comics' Swamp Thing from the 1990s). If the substitution was "animal" damage, perhaps the target is swarmed by insects... It might have to be limited to conjuration spells, but who cares?
Instead of shapeshifting, perhaps they have increased and unhindered movement in natural surroundings. At higher levels, they would almost seem to teleport...
Some non-exclusive ideas:
The SS has one feature that I like that is underrepresented in D&D- its a class centered around an animistic worldview. They derive their power from working with the spirits that inhabit the world around us. Take the SS and boost its link to the spirit world, let them converse with them, learn from them, gain power from working with them.
Another possibility would be someone who can self-buff based on his totemic animals. A totemic character might also be able to take on animalistic abilities- akin to what happens with Eberron Shifters.
Perhaps like in Michael Moorcock's Eternal Champion story arc, he derives power from pacts with nature deities. (This would be best modeled by something like the Binder.)
You could have them choose Domains, like a Cleric, but limited to the various nature-themed ones. In addition, as they level up, give them characteristics based on those domains akin to the Drift mechanic of the Geomancer.
Equip the class with a bonus and slightly broadened variation of the "Elemental Substitution" feat. In addition to the usual, add appropriately themed nature sources. Example: Flaming Sphere- a direct-damage area-effect spell- could be modified to do "plant" damage. How does this work? Like this: someone within the sphere of effect is attacked by woody plant roots intruding into the skin, or plants that they consumed blooming and growing painfully within their digestive tracts, or the like (see issues of DC Comics' Swamp Thing from the 1990s). If the substitution was "animal" damage, perhaps the target is swarmed by insects... It might have to be limited to conjuration spells, but who cares?
Instead of shapeshifting, perhaps they have increased and unhindered movement in natural surroundings. At higher levels, they would almost seem to teleport...