If we are making DoS2 comparisons all the companions in Dos2 are chosen ones of some god or devil, but they also had their own motivations, goals and companion quests to fulfil. Also, you find old friends, enemies, acquaintances, etc in the world if you take that companion with you, as with any companion in other games. The only thing I found lacking in the companions is the fact that they do not talk to each other, but their stories? they are far above the level and depth of the average CRPGs today.
The fact that all of them are sorcerers are the reason they are together on the same ship, but they have very different reasons to be there and you can achieve different endings of their subquests in the game.
Lohse wants to get rid of the demon inside her, Sebille wants revenge in his slaver and she discovers her true origin in the game, the assassin Ifan wants fulfil a killing contract for personal reason, has a dark past and seeks revenge in the divine, Beast is a rebel fighting the dwarven queen, and the Red Prince is a former prince of the lizards exiled and with a shared destiny that he has to reach (or not)
So I do not think that having an origin story has that huge impact on the resources and cut a lot of content of the game, at least that doesn´t happen in previous Larian´s games. In fact, the origins stories give you a lot of reasons to replay the game to see how it plays out if you do things differently with another character.
