I think that's kind of the same issue as the "you're reading it wrong!" one... an editor who made any comments just wouldn't be able to understand the perfect vision. Obviously, the changes he or she suggests wouldn't be useful to clarify a sentence, because it's already the epitome of sentence-ness!

...Everyone needs editors, if just for that other perspective. Of course when you edit your work it'll be clear what you meant to say - you wrote it, after all. And that can blind you to inconsistancies, lack of clarity, ambiguous statements... you need someone else to look at it with a fresh view.