Interesting. I can imagine they would have polished some elements for the final script, even if the part was originally written for a man. And of course, Ridley Scott would have improvised certain nuances on the set. But your general point stands (and it is a rather depressing one).

On the other hand, the same cannot be said for James Cameron's Aliens. Yes, by then the character had been established, but I think Ripley's character arc in that film is remarkable. :)