With such a quote war going on I don't know who is saying what, lulz. Just going to reply to nobody in particular: The main advantage of writing pre-made companions is, *drum roll....* being able to logically tie them to the whole and develop their idea! In a PnP session, it's pretty much impossible to do such a thing if you are improvising. The same way a huge musical idea can't be done while improvising and it needs to be thought up and written down. Beethoven can't improvise his 9th Symphony :p. If you don't do this then the companions become token and they aren't any better than adventurer's hall husks. They literally mean nothing and they can be substituted with *anything*. That's why writers are on the team, the main plot can be written on a napkin by the janitor and it would serve its purpose. This is what writing (any kind) is about - developing and expanding upon an idea and the elements of it to form a coherent, logical whole. Everything else is dilettante-ish scribbling which amounts to nothing and goes nowhere. Climaxes, changes and everything else that has to do with the plot, are all necessitated by the involvement of the characters within it and leading to a logical point where these things are forced by their actions and don't simply happen because we have to go somewhere with this whole "plot" nonsense.
It feels like I'm beating a dead horse here, but so many video game writers treat the writing like some random slice that is their pet project rather than a mover and shaker of the whole. That's what Chris Avellone gets and that is why he is such an outstanding writer, his characters *matter* and are the focal point of the whole narrative. That is also why it's so coherent, logical and satisfying. This also comes with the perk that by tying the plot to the characters you are less likely to trip over plot holes and inconsistencies that jar you out of the story and break the fundamental principles of storytelling.