Post History

> Quoting parts of questions in answers is a problem because it prevents the legitimacy of a question's OP to try to improve a bad question in case community members think the question is bad by heavily downvoting it, let along, explaining severe problems unclarity or misleadingness in the question.

If the question is so bad/unclear that it risks getting closed or simply can't be answered, then it shouldn't be answered. Those who answer anyway with speculations risk down votes too. So the scenario you describe is quite unlikely.

Now in case a question wasn't bad but it needs a drastic clarification - "this applies to both X and Y, which one are you asking about?" Then that's problematic too. Suppose someone gives an answer about "X", then the OP changes the question so that it's now only about "Y". This turns potentially good answers into bad ones and off-topic at that. Such changes to the question should not be allowed once answers have been posted, in case the changes make the answer obsolete. This is the standard scenario for an edit rollback of the question. Better then to ask a new, narrowed-down question.

Otherwise if the improvements of the question are minor and there are answers quoting old revisions, the answers should be possible to edit into shape. If it isn't possible to do so because it would change the meaning of the answer, then those changes to the question shouldn't have been made in the first place.