For kind 1 events, simple replies are sufficient for making corrections and adding comment/context. And replies require the commenter to do so from their own account, attaching their own name and reputation to their comments. Allowing others to suggest edits to someone else's post is bothersome at best, and depending how it's implemented it could form a "mob rule" style of censorship. For instance.
Discussion
I get where you're coming from. Playing with it, it definitely needs some kind of visible history so you can see who/what/when. There's no accountability or transparency at all. Right now it's full-blast-wild-west-free-for-all editing. I can see scaling being an issue when relays are storing all this edit data, also.