I really which grammar comments could be replaced with a "suggest edits" feature like on Quora. I don't know why no one has created a javascript layer that can be added to a site that would allow the author to designate anything on the page as something for which readers can suggest edits. Then when a reader clicks an edit button, they get an interface just like on Quora or maybe even better, where they can make changes and send those diffs to the author, who is free to apply them.
I couldn't concur more. It's one thing if someone is tactfully offering a suggestion that would help improve the comprehension of someone's work.
But to me there's nothing worse than someone whose only way of adding value is criticism something they weren't creative or proactive enough to do themselves.