In review, I've seen a number of edits that were good ...except for the edit summaries.
Bad summaries are most often something like, "Improved question." This is a bad summary because any editor assumes his/her edits have improved the question, or they would never have suggested the edits in the first place. This provides no information whatsoever about what is changed, and is worse than putting in no summary at all, because with no summary, Ask Ubuntu generates a basic, purely syntactic summary of the edit, which is often somewhat useful.
So far I've just largely ignored the problem. When I think the changes made by an edit are good, I approve the edit.
But the number of users applying these bad summaries seems to be increasing (though I do not intend that as a scientific claim). I feel like I shouldn't simply ignore this.
But what should I do? Here are some possibilities...
I could reject the edit. But I don't want to do that, because the actual changes are good.
I don't think I can "Improve" the edit (with the "Improve" button)--edits that change only a summary are not accepted by Ask Ubuntu.
Should I try to contact the user personally?
Should I post a comment? I don't want to pollute questions and answers with these kinds of comments (not even directed at the original poster).
I could post a feature request, asking that the edit summary text box carry a more explicit statement of what it's for, or for phrases like "improved question" to be automatically detected and rejected as edit summaries.
Or I could just go back to ignoring this, as I've been doing until now.