It's been noted (in some blog post) that there are three types of users on SO: question askers, answerers, and editors.
Editors are somewhat the unsung hero. Unsung in that, well, there are badges, but no rep, even though their work is really important to the site. Editors are the reason many, many questions survive at all, yet the questions (and sometimes answers) they edit receive upvotes and rep, for the hard work of the editor.
I propose +5 rep for an edit, once the post the edit was made on receives an upvote from a user other than the editor. This isn't a large amount of rep; just that of one upvote. But in many cases that upvote was able to happen precisely because of the edit, so credit should be shared. I am also open to +2, the amount rewarded to a novice user (<1k or 2k rep) when an edit is approved.