We're already given two choices for the player: either a heavily scripted Origin character or a blank slate for roleplaying.
A middle option with some kind of "light" personal quest would be hard to pull off without steering too far in one of those two directions. Too much scripting and it would feel like your story is on rails, not much different from choosing an Origin character. Too little would just be a "meh" side quest with no real impact. That's without even getting into how it would have to fit each race and class.
It's an interesting idea, I just don't think it's practical, considering the opportunity cost in developer time that could go somewhere else.
I don't disagree with you. It would certainly pose a lot of work for the developers, and it would be difficult to have quests that strike the right balance between fun and fulfilling, but not too much on rails. It's part of why I thought tying it to background choice might at least help with that, in allowing people to still select what most closely matches how they envision their character.
In a related note, I do wonder if the origin characters will be treated the same as those in DOS2 where you could tailor their class how you liked when you selected them as your main. I get the feeling you won't be able to do that in BG3. I'm not saying that's bad, but for those who want to pick their own class AND a background that comes up in the game, I have the suggestion above.
But, as said before, I'm well aware it would be quite difficult and a lot of effort and other things take priority right now.
