One invocation and one cantrip...that puts this feat on par with something akin to Spell Sniper, so power-wise, it seems legit. Although, the Eldritch Blast + Agonizing Blast combo seems a bit overpowered; given the level requirement, it makes more sense. Although, that would make the sun soul monk a bit of a rival.
I'm not too good with Hexblades, so can you explain this please?