I take it you're not satisfied by the Shepherd druid? Or maybe you'd like a different take on the concept?Shadow spells would definitely be nice.
I think the main thing truly missing that’s a big archetype is a Summoner. Not sometime rarchetype that has access to a bit of summoning, but a set of options for focusing on being a summoner. Maybe that looks like a horde-bringer on one class, while another class gets a sub that focuses on bringing forth one really big bastard at a time, and the class gets unique spells at high levels that bring real big stuff into the world for just a moment, manifesting awesome weal for the PCs or woe for the enemy.