First of all, the oath seems... flavor inappropriate? I guess to me, the idea of that fey don't make leather armor or weapons seems alien.
Second, I feel like being a prepared spellcaster is the wrong choice for this type of character, at least, power wise. They feel like they can honestly do a -lot- because of that. If your goal is to make a tier 1 one class that can go toe to toe with the druid though, then I don't think this is a problem.
Finally, from a design standpoint I dislike the dead level at 19th, and the continued use of 1d3 for unarmed damage (it's an awkward dice size I feel should be moved away from when possible).
Overall, it does look pretty good, I just think it could use some more refinement and punch.