I mostly just based them on what a Harry Potter character can do.What was the theme you had in mind when picking the expanded spell list?
It acts as a foci regardless of class, but that doesn't help outside of multiclassing.Also, the 1st level feature is super-weak. I could just but an arcane focus on the shape of a wand and get the same benefit.
Edit: no, it's worse than that. An arcane focus is already part of the warlock's default starting gear. All this feature grants me is that it only works for me. Is that ever gonna matter?
You're right that it's weak. I'm considering having it able to be summoned as a free action, so you can never be disarmed, but would that be enough? I don't want to put too much power into it, because it gains quite a bit of power later?