I've had a fairly long career in consulting to this point, and I don't expect it's real close to its end. Over the course of that career, I've had lots of work reviewed and often reviewed the work of others. The question that I would ask is this: "When someone asks you to review their work or when a client asks a third party (you may be the third party) to review your work or the work of another, what should that entail?"
Clearly, step one is to make sure that the work that was done is correct. Other important tasks for the reviewer are to make sure that the work product is appropriate for its intended use and appropriate for its intended audience.
How about checking to make sure that a document or report is well-written? I think that is part of a review as well. But, where does that start and where does it end?
If the original author will be the signatory, does that give the reviewer license to alter the author's style? In my opinion, it does only if the original style detracts from the intended purpose. On the other hand, it does not, in my opinion, give the reviewer license to re-style a piece solely because he or she has a different style than the original author.
How about word usage? Should the reviewer express their own opinion by making word changes where the two words have identical purpose? This one is a little bit trickier. Suppose the author has used the word "will" and the reviewer changes it to "shall." What do you think? I think the reviewer is making a change for the sake of looking important. On the other hand, the reviewer does need to consider the intended audience. If the original author, for instance, has used the term phonetic syzygy (I was grasping for something fairly obscure), would the reviewer be within his license to change that to alliteration. I think he would, because most audiences (I don't think) have any idea what phonetic syzygy is, so the word change would make the document more readable.
When the whole concept gets really sticky is when you are a third party reviewer being compensated to do that review. If you don't make many changes, are you earning your keep? Is it okay that you are saying that the author did a good job?
I think most of us struggle in this regard. If we are asked to do a review, most of us seem to feel as if we have come up short when we return the document in a less than bloody state. As an author, I despise this. When I'm a reviewer, I hope that my original authors hate it when I do the same.
Many of you had the fortune or misfortune (it's your opinion) of reading the works of very different authors during your schooling. Consider, for example, Messrs. Faulkner and Hemingway, widely considered two of the great American novelists. You may have an opinion as to which of the two was better. I do, but my opinion here doesn't really matter. The point is that if Faulkner had been asked to review Hemingway's work or conversely, and the reviewer had pushed their style upon the work of the other, then America would have been short one style of writing.
At the end of the day, if you are asked to review, do your job. Doing more than your job is probably not your job.