hello there.
The main problem of DOS2 playing custom character was that it felt pretty much empty compared to origin characters with full quest arc or their own. And who doesn't want more content? Thus nobody played custom characters
BG 3
By now, apart from [Baldurian] and [Underdark] tags our custom characters is a blank sheet. Again. And again compare this to any of the origin characters(for example, you are a vampire spawn, who seeks to become free of his master, that's a backstory) and your choice will be obvious, because origin character = more content.
I know, if Larian didn't plan to create a custom character quest arc from the beginning, they wouldn't do it now just because of this post(or any posts really, it would too hard to implement by now), but they must provide with something. Something that makes you "oooh i'd rather be playing my custom lolth-drow sorcerer than Shadowheart"
Suggestions
1) Ideal approach is to give us full backstory(how did we get snatched by mind flayers, what are our connections in this world and so on) and a quest arc(what problem we solve apart from main quest based on our backstory). It is very in the spirit of dnd, because when you play tabletop, your character backstory is very important, because it basically motivates you to become an adventurer. And a good DM will find a way to connect global plot with your backstory
2) I don't know what a realistic approach is. Maybe some text-cutscenes of your backstory? Or just one cut scene? And then maybe a small quest arc that ends in act 1, so there woulb be no long lasting permutations? I don't know, let's discuss
