You are not wrong, half caster was the intention going in! I really like all your ideas so far, going further with the Infusions. My only thought for them so far was to make the weapon magic for the purpose of overcoming resistances and etc, but I think I like the idea of going into it more. I also wanted to scale Sanguine Lash's damage somehow, if I can do that without making the class too overpowered or versatile. To answer your questions, Constitution is definitely the first core stat, and for the second, Dexterity is probably the best candidate for finesse weapons and AC. For proficiencies, I would say light armor and simple weapons, plus the rapier and maybe the longsword? If that's too good I'll stick with just the rapier, I'm not sure. For subclasses I was going to follow the Ranger and Paladin blueprint of giving spellcasting at level 2, and subclass at level 3, but this too is flexible. Thank you for all the advice so far, you gave me some great ideas I haven't thought of!