Yes, I agree, but as one of the other comments say, they are not able to read your mind. So even if the structure and style is not clear, you must be able to express what you want.
Certainly. I just think "expressing thoughts in words clearly" might in the end turn out to be something different than what we, humans consider clear.
For example long unstructured rambling might turn out to be a non-issue, while as human I would rank such message low no matter how good it is in other informational aspects.
That's true. I feed Codex some very long .md files that I use as a kind of work diary and that are pain to use into something very much usable. Writing your thoughts is important even if done carelessly.