Origin characters water out the narrative focus of the story, I feel. Baldur's Gate 1 and 2 were about a single person, Charname, Gorion's Ward, the Bhaalspawn. We could change the attributes of that person, but that person and only that person was the focal point of the story.
Origin characters water that out, turning the story into an unfocused mess where it's not about any particular person, but about whomever happens to randomly be at the right time and place. It could some wimp of a vampire spawn, it could be a brainwashed cleric of Shar, or it could be some Githyanky teenager with the usual teenager emotional issues.
And frankly it feels like rather than having any dedicated protagonist, the game might actually end up operating with "the group" as the protagonist, meaning all of the above could be the "special one" at the same time, meaning the "special one" in the story really isn't special at all. Frankly this sort of narrative approach feels more like an Icewind Dale sequel than something trying to be Baldur's Gate.
The original games had awesome companions, by the way, in no small part because they were designed to just be companions. That made them separate, it made them more unique, and it made Charname more unique. Partly because there was always just one charname, and partly because you could team up with people that weren't actually bhaalspawns raised by Gorion.
As for the origin story bit, I really hope they tone it way down relative to DOS2, because the idea that players should be pushed into playing pregens and essentially punished for making their own characters is ludicrous and the opposite of what I feel is the spirit of D&D. Can you imagine turning up to a session and then the DM just has a stack of characters ready, asking who wants who? Nobody wants these people? Fine, no backstories and cool nonsense for anyone, then!! That DM would not be popular, would he?
