Adding Shillelegh to the Warlock list is potentially dangerous, I think-- Magic Inititiate has a lower cost than a one-level dip, and now anyone who wants can simultaneously pick up casting-stat-to-attack, the best ranged attack cantrip in the game, and the best first level damage boosting spell on the game in one fell swoop. I'd prefer to see Hex Warrior as an Invocation, to make the relative cost a bit higher.

Eldritch Curse strikes me as unnecessary-- it has pretty much the exact same thematics as Hex, but in a generally-inferior way.