While I don't presume to speak for Editorialdom, I can tell you what my three boyos - Thorny, Steve, and Mike - are doing with "Winter's Woes".
1) Mistakes. I write like I think, fast and casually. The editors catch an amazing amount of flubs. Otherwise, the reader distractions would be … um, distracting.
2) Critical Analyses. For example, in "Woes" I had lazily ignored the actual process necessary for an insurance company - Oasis - to take its products to market.
3) Perspective. It's easy for a noob to fall in love with her own prose, to become lost in the gorse. At the expense of the narrative. Cogent editorial reminders - "You stupid bitch!" - can be useful.
4) Ideas. While perhaps not so fungible, a creative rethink can suggest new directions. Such as starting a new series featuring Walker. Or Vanessa. Or Pilar. (In this instance, I'm more likely to follow Robert B.'s example and construct an entirely new character that peripherally interacts with Winter and crew. Like Sunny Randall. And Jesse Stone. Both in Spenser's orbit.)
Overall, are editors a plus, a cipher, a negative?
Hmm.
Paige