Granted, the mass culling idea in BG3 wouldn't be so bad if it turns out there are actually going to be more companions joining you after Act 1, meaning that the potential culling only involves like 1/3rd to 1/4th of the cast instead of 1/2 in DOS2. Though Larian also risks what happened with PoE2, where much of the community considered the 'sidekick' characters that didn't have full companion status to have much more interesting backstories and depth compared to the full companions. Of which most of the actual companions the generally acted as extensions of each of the game's factions, rather than being their own thing with actual agency.
The Origin system existing in BG3 is probably already set in stone at this point, but I hope that Larian is experimenting with companions that join you after the assumed culling at the end of act 1 and thus not being origin characters either. They'll probably be taking notes on how writing companions not constrained by either gameplay mechanic works out in comparison to the origin companions. I'd hope they wouldn't be surprised when they end up becoming way better received than most of the origin companions.
But I did notice something curious recently. Right now some of the dialogue options here and there have tag "Baldurian". We can't decide to be from Baldur's Gate when making our character, but some of the Origin characters are. So already it seems like there's just going to be more interactivity and reactivity when we pick Origin pregens rather than playing our own characters.
This is something that has leapt out to me throughout the EA so far. The complete lack of any progress on the background tags would make me rather surprised if custom characters ever got anything else but a Baldurian tag in the end. I want to play a Waterdhavian Bard for instance, as my own personal tabletop character is currently involved in a campaign taking in the Undermountain underneath Waterdeep, and I would expect unique dialogue from Gale when he talks about the Yawning Portal in particular.
Backgrounds are a huge part of the identity of DnD, and it's obvious at this point that development on that front is being sacrificed for the origin system.