When to beware of an editor
Some editors are most likely frustrated writers who vicariously would "take over" authors' works in progress rather than risk diving into the creative pool with their own projects. They claim literary expertise as badge of privilege while they try to hog in on their clients' talent and worthy efforts.
Other editors are simply control freaks, savaging writers bravely earned chapters until there seems to be more red ink on most pages than black. They're insistent that their edits deserve to be written in stone, in denial of the truth that writers have sole authorship of their work.
Still others, as well as some of the above, strongly imply to assure what they cannot: that fortified with their editing a writer's work is almost guaranteed to "sell". This can be the most seductive assurance to a new writer—until the dawning realization that one has been taken in by a near certainty he or she so wanted to believe. For the record, this editor has no publisher or producer in his pocket, and will make no false promises. Nearly all writers who want to sell their wares have to trek from door to door, having them repeatedly slammed in their faces, while maintaining the courage to have faith that if they keep at it, eventually they will be welcomed in.
If an editor's primary purpose is anything but honoring an author's intent in the art and craft of story development, that editor is toxic.