There is typically very little discussion on what constitutes good editing of academic prose. I've been through the editing process in a number of different formats, both through major and minor print journals, electronic journals, and books chapters. I've also been the editor once, and found that there were a good number more choices to be made as an editor of academics than I had suspected.
Typically, I have had few, if any, problems with edits that were suggested, since typically, they were edits made to conform to house style, or simple proof-reading. Although when I was an editor, I did have to be a bit more active and hands-on with my edits. In one case, the author specifically gave me license to edit his very theory-heavy prose for readability, and while I think I did a decent job at readability, I was also very clear that I wanted him to make sure that I hadn't changed the nuance of anything that he had written. In the other case, the author had gone overboard on the block quotes, and instead of making those edits myself, we went through two or three rounds of revisions where I asked him to make specific kinds of revisions. That was a bit of an arduous process, but I think he felt ownership over the essay at different points when some major edits were needed. In all the other essays I edited, it was my policy to not comment on matters of style if comprehensibility was not on the line. I did not edit out things that I prefer to avoid personally (passive voice, even strategic; overly clunky signposting, etc.), but sought instead to preserve the author's voice with the (admittedly flexible) bounds of standard grammatical structure, a subject on which I am no expert.
I have just gotten back edits on a book chapter however, where the editor (or more accurately, I think, the editor's assistant) has taken a very active hand in re-working the prose. Some of the edits are fine, I suppose, but others change the nuance of phrases, cut whole sentences, or simply re-phrase sentences on the basis of stylistic preferences rather than actual comprehensibility. In a few places, there are comments that say, "This sentence is unclear" on sentences that make perfect sense to me.
In isolation, few of these comments or edits would bother me, but they are so thorough, and so unnecessarily thorough, that it feels like the language was often edited for the sake of being edited.
But my experience is generally limited, and so I pose this query: when either editing or being edited, how much of an editors' fingerprints do you think should be on any given draft? Should an editor of academic prose in a collection of essays be editing for style? How much so? And how do you respond when you think an editor has overstepped what you believe to be a comfortable ownership of the prose?