I dont quite understand what origin characters have to do with Baldur's gate or D&D. Why is this one of the must-have feature of BG3?
Why not? Origin characters take your companions and puts them center stage, you get specific tag lines when interacting with other npcs for said character. Kind of wonder how many people are going to play Shadowheart when it goes live...
D&D has done this, off the top of my head I know there was a board game/card game that had pre-generated characters you played as.
Here, took me about a minute to search for it, youtube vid of neverwinter nights at 1:03 Create New Character or Select Premade Character