Why does having multiple important stories integrated together crate narrative issues? Is it because we are programmed to love and follow a single hero and there has to be a solitary leader figure that pulls everyone forward through the story? Why can't there be a team of equally important and different characters and the team as a whole is the "hero" that pulls the world through the problems and saves the day.
The issue I have is the execution, not concept itself. As the only human player I have influence over what we do, where we go, how we do things. As such my PC is the leader of the group when I play in singleplayer. Narrative and gameplay need to work alongside each other. Creating NPCs which would feel like independent selves with goals, agendas and equal to us influence would be quite a feat, and could be interesting. But it is not a story that singleplayer D:OS2 (and I assume BG3) tells.
I don’t know how well will BG3 fair in making companions feel like independent, thinking individuals, but D:OS2 was a failure in that regard. None of the companions felt good to me (my full D:OS2 feedback). A way, in which we interact with NPC and human players is simply too different. You want to design an RPG were our PC is a part of a group, rather then a leader - that’s great, and interesting, but it needs to be designed differently. As it is, we have a complete control over our companions actions, and even decide what they get to say. Bioware approach solved this dissonance by putting the player in a role around which the game revolved. Whenever you were Bhaalspawn, Raven, Gray Warden, Spectre etc. - it made sense that companions would follow you. They might have their demands, and leave you, but otherwise, they were under your command.
D:OS2 didn’t do that - companions were created to be inhabited by other players with their own wants, and without coop buddies, companions just felt empty. And unlike other RPG, D:OS2 had nothing to explain in narratively. D:OS2 companions will neatly fall in line, because you are the only real player, even though narratively it makes little sense. Imagine ending of BG2:ToB where everyone is the child of Bhaal. Why are you the one to ascend? In BG2 other candidates (Imoen, Sarevok) have reasons not to contest you. In D:OS2 they don’t, because they are supposed to contest you - you are equals. But they won’t, because you are the only player, therefore the game revolves around you. (I know it’s possible for companions not to ally with you, but it’s unlikely they won’t and if they do, it sucks). D:OS2 companions have good moments, but those are traditional ones - helping them solve their own side adventure. Whenever companion’s wants cross player wants it’s just doesn’t work.
On a side note, I didn’t like playing as origin either - I am not blind to benefits of pre-defined characters, but I felt distanced by Lohse’s or Grey Wolf’s definition (those were the two I tried myself) - not defined enough to be engaging, yet knowing NPCs and things that I don’t.
So yeah, good system if you play with a buddy and your attention is directed at your friends, with PCs being little more then player avatars. For single player world building and storytelling - just a bad system, leading to weaker protagonist and companions.