Thank you for posting this feature request! Attribution / recognition for authors of wiki edits is as important as attribution / recognition for authors of comments. For threads with a wiki topic, more often than not editing the first post might bring a value equal to a comment, if not more.
I think the current UI could take this feature without changes, except counting comments + wiki edits. There is no need to make big differences between contributors of comments or edits? Just add the avatar of authors of edits as the authors of comments are added: Plain avatar after “Links” or in “Frequent posters”, with number of (comments + edits) if more than one.