So far I've reviewed about 15 edit suggestions, 3 of these I rejected. All for the same reason. Deviating from the OP's intent.
This would be a fine edit from the OP, but not from another user. THe comment part is okay (the OP replied in comments with "a simple reason will suffice, but I don't think it's too broad"), but the "to address some of the comments..." is not okay. It's basically pretending to be the OP and doing something under his name.
This one is closer to okay, but still not. The title edit is fine, but the last paragraph, again, is basically pretending to be the OP. That's not cool. It's mostly the "pretending to be the OP" part that I'm talking about here.
Also note that both of these questions were in the process of being closed, but that doesn't really matter. It explains the motivations, but it's still not allowed.
The editor also left a comment saying "@AlexanderRossa I hope you appreciate the image I'm adding!". (just noting this, it doesn't really make much of a difference)
This is a fun image, but there's three problems. First, it's completely unrelated to the question part, i.e. the "how can I do this" part. It's only tangential to the subject matter anyway.
Second, SE hates fun. Fun(ny) images don't below in questions.
Third, like the earlier examples, it simply deviates from the original question. If the OP added it, I'd edit it out due to the first two reasons though.
Why is this a big deal? Because we currently have 4 users with the ability to review suggested edits. (almost 5!) Each edit takes at least 2 people to review, unless one person clicks the "improve edit" or "reject and edit" button. Yes, the OP can approve it and only one edit is required, but failing that...
Let's not waste the time of the few reviewers we have, eh?