This only counts the last editor on non-deleted posts, so it's very incomplete.
Q&A for SharePoint enthusiasts
select top ##Limit## rank() over (order by count(*) desc), lasteditoruserid as "User Link", count(*) as "Edits" from posts where posttypeid = 1 and lasteditoruserid is not null group by lasteditoruserid order by count(*) desc ;