Some of the work I had to do was non-technical. I would often find myself translating and rewording awkwardly written passages so that they sounded better (the author is a non-English speaker).
That said, Packt is pretty hands off and don't micromanage (which I actually really enjoyed). Most communications that I had with them were initiated by me when I felt things needed to be pushed along during the review process. That said, in the end, a book was published, so I suppose even if the process leading up to that moment was not completely optimized on their end, the end result was a successful book.
I decided not to go ahead because I'm a perfectionist - I'd want to write a damn good book and the opportunity cost loss of earnings whilst I was writing the book didn't compare to the relative prestige of saying I was a "published" author.