I agree with most of your points. To add a little bit:
Astarion
Allow him to become a full-fledged vampire on his good path [it's illogical he doesn't, he has Cazador right there and can drink him to become stronger without ascending, just your regular vamp business as previously explained by him].
And then allow him to turn the PC as well for the fun of it (giving them an actual choice in the matter this time with neither yes or no breaking the relationship). It would be an entertaining scene, I'm sure, and I'd love to see it!
Ending + Gale
Allow me more evil-ish ending options.
Let me keep the Crown and decide what to do with the world - give the option of current ending with all the mindflayer stuff and becoming brainwashed Absolute repeating some bs about "all hail me", but also give some other ones, lively ones that fit different characters. Taking over Baldur's Gate, chasing immortality, getting rich af and living the good life, going to Avernus to mess with the devils, anything really that humanly and fun and corrupt, but in an entertaining way!
Let me give the Crown to Gale as we have agreed and see what he does with it!
I think those are my two biggest wish points not mentioned in the posts above
