I came upon a question where I wanted to make an edit, but I wasn't sure if it would change the original meaning of the question - as I did not know enough about the subject material to be sure.
I could wait for another user to come around and make the edit, but perhaps they wouldn't notice the problem that I wanted to edit. I could also suggest the edit in the comments, but it is such a minor nitpick of grammar that I seemed like a waste of a comment.
Of course, I can't just let a minor grammatical mistake go unnoticed.
So my suggestion is to allow an editor to mark an edit to instead be suggested to the author for approval, if the author believes it does not sufficiently alter the meaning of the question. It would pop up under their usual notification area to approve or reject a suggested edit.
This is different than the 5k/mod suggested edits version in that it would be from a user who could have edited the question, but still seeks the approval of the original poster.