This is a weird use case. When I have the time, I tend to edit questions and fix relatively minor stuff - spelling, grammar. I'd re-word something or re-write a sentence if the current version doesn't really work.
I'm afraid of making bigger changes, however. Sometimes I feel like I can re-write a few paragraphs to make the post cleaner or even trim unneeded information, then re-write the rest of the text, so it fits. But that seems like a drastic change and I'm especially wary of missing, changing, or adding details to the edited version that don't correspond to the author's intention. My goal is to preserve the meaning but make sure it's conveyed better.
So, I though that perhaps I can take the current question, then re-write it and post it on the Sandbox, then invite the question author to have a look and further improve the question, if needed. Further improvements could be done by me, the author or anybody else.
The expected outcome is that the original question would be changed to match the version in the Sandbox. I am not interested in posting the question for myself. I think it might be especially helpful with closed questions that I think I might be able to correct to be re-opened and answerable.
The process would be broadly similar to suggesting an edit as a pre-2k rep user and having it approved, improved, or even rejected. It's bypassing the suggested edits since I can't really submit edits as suggestions with my rep (as far as I'm aware). Moreover, the edit is likely going to be a lot bigger than correcting mistakes, so a more thorough reading would be needed. Lastly, the original author should really have more say than just other reviewers, as it's important to make sure the intention is preserved.
This is something that I think would be of use to me, personally, in order to help out users with their questions. I'm not in any way expecting other people to start re-posting edited questions in the Sandbox.
Hopefully this description is clear.
Would it be acceptable to take a question from another user, then post an edited version of it in the Sandbox?