I like the idea of getting approval/feedback from the community when in doubt over the usefulness of a certain edit. However, if the Super User Suggested Edits review queue is anything like the one on Stack Overflow, many reviewers work their way quickly through the review queue and don’t pay much attention to the usefulness of the edit (presumably to accumulate another badge).
I sometimes see useful edits being rejected with no other feed-back other than the stock “no improvement whatsoever” reason and on the other hand, I see bad edits being blindly approved. (I have less than 2k reputation here, but on Stack Overflow and Unix & Linux, I usually check the question or answer of the suggested edit in its original context to make a useful judgement.)
Personally, when I’m unsure about a certain course of action, I’d prefer to get qualitative feedback (e.g., reasons for/against) so I can use that information to make a better judgement in future similar cases, but with the Review queue, a particular edit is often often either approved or rejected without any useful feedback.
I’d agree with David Postil that more useful feedback would be gained from the community by posting on Meta. There may be ambiguity over the results of the discussion, but at the very least, you’ll become aware of consequences or other factors that you might not have considered and can make a more informed decision.
To clarify, I’m not against this proposal (I would’ve downvoted if that were the case) as I can understand some users might want a simple yes/no as to whether an edit is useful or not. It’s just a feature I’d be unlikely to use.