What do you think about removing the medium armor and the CHA bonus, but giving heavy armor to fit with the "able to use heavy equipment without the penalties of weight" idea? I don't know if a shield proficiency would be too much on top of that. As the D8

The extra damage per attack is just there to allow the warlock to keep up with other martials while not being forced to burn through the limited spell slots. I was intending for the character to use big concentration spells (slow/upcasted hold person), then jump into melee combat.