I've been silent recently because I was working on a project that emerged suddenly.
I do a little ghostwriting on the side, and one of my regular clients emailed me for a quick edit of his latest book manuscript. I had only a week to go through about 40,000 words. I edited, made my own additions, streamlined the layout and formatting, built a table of contents, and generally got the prose up to publishable quality.
As an editor, I find it difficult not to inject my own thinking into the text. Theoretically, I'm supposed to be non-interventionalist, which means not to futz too much with the prose. Just correct obvious errors and smooth out rough patches. These directives alone can keep me busy enough. My client loves to begin sentences with "and" and "but." He also switches from "you" to "we" perspectives constantly. He often relies on strings of cliches too. These areas take lots of work and attention. Nevertheless, several opportunities always arise where I need to re-phrase a statement or to add another phrase or clause for clarification. In these cases, it's my sensibility that becomes sutured into the text.
The person with the "pen" on the text always has a curious power, although it's certainly not an unlimited power. Heck, it's often not a lot of power. Yet, we can never be certain that our received texts are univocal. Indeed, I'd wager that very likely none of them are, and we're not even talking about texts in the Barthes-ian sense, texts as tissues of other texts.