:You don't think  pushes editors away?  Like Demiurge said, they may not be experienced, high-profile editors that leave in a huff with a big "Retired" sign on their user page.  In fact, those types of editors are less likely to be pushed away by KW, because it's more likely that they understand the situation better.  But, imagine the response of people coming here for the first time who are greeted by a message that is equivalent to "Don't edit this page if you're an idiot.  You need to have a PhD or higher to edit this page."  Not cool. 
 :Anyway, I agree with Demiurge that KW needs to hear that his behavior is problematic from everyone.  If you're someone he talks to regularly, then he needs to hear it from you too.  No sugar-coating the truth to make him feel better, as even one person doing that will encourage him to misbehave again.  I'd be willing to consider (not promise) restoring his talk page access about 24 hours before the end of his block, if you have something to discuss with him and if you think it would help to ease him back into editing.  I'll think about it over the week.