A way to make a custom character better in my opinion is that, instead of race dialogues, add personality dialogues, let us have choices that change our character morality to more evil or good, and with that unlocking different dialogues based on choices.
Like I play as a good drow follower of Eilistraee, and it's weird that I'm supposed to have many of the dialogues that are from the basic Drow race, and on them it makes my Drow seems rather evil, unpleasant, etc.
This wouldn't just fix the, oh, such race is evil, or that race is good, so they can't have X dialogues, etc. Take Tieflings, I know ppl who want to play evil, but the Racial dialogues are basically a really good alignment, so it kills the immersion to anyone wanting to play with more freedom in this regard.