Well, as someone pointed out on RPS, Blade Runners Directors Cut did rewrite itself. Don't know how valid this claim is though, might be someone here that has seen both versions.
That said, I do agree with your point. Rewriting the ending is a really bad idea.
I really find it funny to read all the peoples wishful thinking and denial-fu theories about what the ending really is. Just so that they can feel good about the ending!