The screenplay part made me think. While it's true that an LLM could potentially generate a better^ script, while writing scriot the author would probably had had many ideas that did not make it to the final draft. Yet those ideas would definitely influence the final product, the movie. There's probably only so much you can put in the script really.

Meaning for the brother is one thing, but as a potential watcher, I would almost always prefer a movie that someone really cared about^^.

^: depending on the definition of "better"

^^: as a fallible human being I am not perfect at detecting that care, but there had definitely been cases in my life when someone was talking about a thing that I would not really care about otherwise, but their passion made the talk extremely interesting and memorable