If I as the player find her to be evil, then she is evil.
lol, sry this just reminded me of the anakin quote from episode three
i actually dont think i disagree with your overall sentiment - i just think that alignment should be a working function of a bg3 game based on 5e. if larian includes/improves it where it impacts the gameplay in a meaningful way that, as you said doesnt set up biased roadblocks within the game preventing you from treating SH as evil, i think it will be real successful - i just want to see it first.