From the FAQ on Meta SE on deletion:
You can't delete your own question if it:
has an answer with upvotes (even if that answer has a net zero or negative score)
has an accepted answer
has multiple answers (even if there are no upvotes)
has an answer with an awarded bounty
You can't delete any of your own posts if you've already deleted five of your own ...
As mentioned in another answer there is no need to delete an answer when you accidentally turned it into CW. Moderators can change it back to a normal post.
All you need to do is get our attention. The best way to do this for things like that is to raise a flag "in need of moderator intervention" on the post and to briefly explain the issue.
You say that:
Sometimes poorly formulated questions contain enough information to both answer them, but more important to find them interesting enough for the community. [...] [P]eople vote to close the question, usually as low quality.
This is how the system is intended to work. If there is a "poorly formulated question" it should be closed. ...
"Now, I can understand the rationale behind the removal, since they largely (though not entirely) referred to parts of the answer no longer present."
That is mostly it. Comments are (very) often deleted when they are no longer relevant. Users can signalize this by flagging as "It's no longer needed." The situation is standard and very ...