All points well taken, Derek. (To be fair, Teymour does address the different levels of editing.) I’d add that, as far as the surgeon analogy, even the best editor can’t fix a mediocre story. Some stories are dead on arrival and no amount of resuscitation is going to help. Also, an editor might be able to fix some things, but the “patient” also has a lot of work to do after the operation is done.
It’s always sensible to follow due diligence in submitting your first draft of your book to an editor by making as fool-proof a copy as possible for you because first, it is your own creation, and secondly, a horrid draft sent your editor can end up frustrating both you and him or her. Make your own corrections to the extent you can, so that will make the job of your editor that much lighter and the end result would be a lot more effective.