I often see movies and read stories that seem to have the possibility of improvement if either things happened differently or additional scenes/information were provided.
If this is something that would be permitted, I have a few such ideas.
Sorry, but the sort of open-ended wishy-washy questions you're describing absolutely wouldn't be a good fit for SFF:SE, nor any other site in the network other than maybe Writers:SE. (but don't tell them I sent you).
What you're talking about are the very definition of 'bad subjective', where there's no right answer and any answers that get posted are liable to lead to unhelpful debate and contradiction.
Per the FAQ;
What kind of questions should I not ask here?
Avoid asking questions that are subjective, argumentative, or require extended discussion. This is not a discussion board, this is a place for questions that can be answered!
Some of these questions, if properly elucidated and specific enough, are on-topic on Writers.SE. However, they are more targeted at things which you are actually planning to write rather than speculation about what somebody else could have hypothetically written. That said, they do seem open to fan-fiction questions. If you're asking because you want to write a fanfic, that stack may be a good fit for you.
In principle, you could also take this sort of idea-generation over to Worldbuilding.SE, but again you should ensure that your question is specific and well-researched.