An idle thought: What would you think if in a review someone included a rewrite of an entire paragraph as an example to address a specific error or concept?
I don't mind that and actually will do it sometimes if I can't think of a better way of doing it- where I struggle is when someone does it and messes with my voice or character's voice and that is the only purpose.
I've not done many full paragraphs, but I do a few lines here or there quite often. Just be careful you aren't hijacking their story. That can cause authors to ignore all your advice.
Please read Constructive Critiques. A rewrite of a section to illustrate an explicitly stated point is acceptable, but just a rewrite is nothing more than arrogant vanity on the part of the rewriter.
It is also similar to an old game in the word games forum, "Rewriting the scene". So if exhibition is your thing, that game is right up your alley.
I don't recall ever including a rewrite of an entire paragraph, but I do rewrites when I'm trying to make a point and it's easier to convey what I mean with a rewrite than an explanation. Now that I'm thinking about it, though, I could probably do a better job of it...
My irritation with this started with a high school English Teacher who insisted my Irish character had a jar of beer rather than a pint. Basically it is when the critquer gives examples of how they would rewrite your piece in their words when they are suggesting something that means the same for no other reason than they want the wording changed. Here is one I remember there have been others of my work. Most of this was a good review but was one i remembered: A little sparrow came and sat down beside him - mine "Another little sparrow" or "A second little sparrow" - their's. No it doesn't work as the MC is not a sparrow he is just in the form of one. He felt, the heat rise inside him and he was all excited. - mine "He felt the heat rise inside him and he became aroused." - umm no maybe complain about the passive voice but to change excited for aroused changes the whole sentence and feeling. Then they tweeted and flapped ferociously. Feathers everywhere. - Mine "They then proceeded to tweet and ferociously flap their wings; feathers littered the sky." - their's, they had reasons for it but it is too descriptive for my work.
Ok, I see. When I think of rewriting a paragraph it usually to completely change the order of the sentences and maybe touch one or two words just to adjust to the new order, so I think I wouldn't fall into one of your examples.
I'd be really annoyed if someone did that to my work. If you think that a whole section should be changed it would be better to say that, state your reasons and suggest the author has another look. Then it would be up to them to make the decision - it is their writing after all! It does sound arrogant to assume that your way is the right way.
When I do tweak anything I point out that it is for illustration purposes only, and that it is not intended to go in the work and apologise if I change the voice too drastically. Where I may do it is to show how to cut wordy pieces, reduce the conjunctions or purple prose etc Or maybe with passive voice or with a first person piece how to reduce the number of I's in the work or maybe to show how a piece may work if the POV or tense were changed. - if what you are suggesting actually says the same thing just differently you should have a reason for that, state it and explain it's just an illustration of how something could be done. For example in the same piece above some people objected to the fact my ancient character used colloquial terms like snogging But that is his voice. The other thing you can do is ask the person would they mind - if you did it before going ahead. Never forget that it is someone else's story.