So ... he's worried that people might make their own characters instead of picking premade ones with cool stories, you know, because when you make a character for a party you want them to be less interesting.
... Huh? How on earth do those two things correlate? I might as well say no banana splits after 2:30PM - hot fudge sundaes only! - because I'd rather you ride your bicycle than take the train.
It's not about Larian deliberately
wanting custom characters to be "less interesting". It's that every response, every line of dialogue, and every quest in the game must be put in by the developers and left alone. The single-player has no human person who can put in NPC's, dialogue and reactions to a backstory which only resides in the players head, and not the game.
So yes, origin stories will have more content than generic characters will. That's just the reality of videogames. They can't match the versatility of a human GM with pen and paper.
Larian has hired an additional SIX staff members just for writing. Paying them a living wage is probably a fair amount of money. It's not unreasonable for Swen to have a preference for players to see the fruits of all the work those writers - writers he's paying for.
If you want to force the player to only use the premade characters, you can simply force the player to only use premade characters. Why put those character creation tools in in the first place if you don't want people to use them? How come I'm allowed to make my own character for the normal single-player game if that's the "wrong" way to play?
This rationale simply doesn't hold water, and I hope Larian rethinks it sooner rather than later.
Swen said nothing at all about hating the idea of allowing 4 custom party members. He said that it probably wouldn't be in at the initial release.
Everyone either has or likely will have some disappointments with the game. It's impossible to please everyone. Try not to take it as you being personally slighted.
I personally have some worries and disappointments about competitive questing and other multiplayer-only gameplay taking up resources which could have been used to make singleplayer better.
