Thanks for the feedback! I recommend you try patch 7. It has barbarians and Magic Missile works a lot better there. You may just have time for a quick playthrough before patch 8 releases.
I agree with pretty much everything aside from the sprepared spells. This is the highlight:
I still don't understand the different shopkeeper tab options (trade/barter), nor have I ever felt a strong pull to try to.

I can’t, for the life of me, figure out what Larian are even trying to do with that system.