Old D&D modules did indeed often come in with pre-generated characters, usually taken from a tournament session or something like that. But usually those were just stats and equipment listings, and rarely were the personalities defined although I think sometimes there were a few high-level traits given, too.
But all that was from a time when the dice rolling for character generation was pretty limited to begin with. Depending on which rules the DM chose, you might have to roll your stats in order, and then choose a class which best suited the rolls. This forced you to play a role you might not have otherwise chosen. But in any case, it was still up to the player to flesh out the personality, make moral decisions, and interact with the other party members.
Playing a pre-made character in a CRPG is very different than a pre-rolled character in D&D. In the CRPG, all your dialogs are written out and your story is already defined. In a sense, playing this way becomes a sort of a living book. That approach can be cool, because the story is very controlled and can be quite deep and interesting. But I think I would still want at least a few story branches to choose. It reminds me of the old Rose Estes books like "Pillars of Pentagarn", where the reader gets a few choices at certain break-points in story, such as, "if you go down the stairs, turn to page 63, but if you go up to the tower, turn to page 132." And eventually you get to one of four different endings.
