While I agree for the most part with the above, there are a couple of additional things I think deserve a mention:

First off, why does the curse not work on mindless things? From what I remember of Hexblade fluff, they're not messing with their enemies' minds, they're messing with their fortune, hence the name. A Hexblade's enemy isn't mentally impaired so they screw themselves over; the universe is screwing them over and they just have to take it. The same applies to the other things that don't work on beings immune to psychic damage, like Crippling Touch.

Second, while mechanically balanced, I'm not sure how Aura of Mettle fits thematically. That one's more of a minor headscratcher. Overall, I'm not sure a support aura makes sense for the class, either Mettle or Protection. A debuff aura would probably be too strong unless it's a Channel option, and there are already plenty of those, but it still seems odd from a fluff perspective.