Ok. You have no argument. All your examples are freely available to develop and use with or without the OGL/SRD. If you want to create d20 product using 3E mechanics and fluff, use the OGL. If you want to create an random RPG product with hobbitty halflings and fox- riding pointy hatted gnomes go ahead, WotC only cares about their mechanics and fluff, let others defend their own IP, i.e Tolkein's estate and Wil Huygen. There is no conflict here. The only conflict is if you try to create a 3.5e slender gnome bard named Gimble and claim it as your own IP. It would be wrong with or without the OGL.
Let's break it down:
Art of Barky 4E dryad= Copyrighted material contact the artist to use it
Millenia old myths, name dryad, concept of feminine wilderness nymph tied to a tree= 100% Public domain. Do what you will.
Mechanics for running a dryad in D&D, fluff about feywild, the name: Black Woods dryad= WotC IP, mechanics will make it into SRD, like all the other examples you listed above did for 3E. The names and fluff wil be stripped off; they are WotC IP. Add the mythic fluff and name back to them if you want.
Even if the 4E Dryad perfectly matched the dryad of myth and legend, WotC would still own the mechanics of how the dryad works in D&D and how the mythic creature fits into its fluffy world. Why? Because they created the mechanics and world fluff; therefore they own it.
