I believe that we should immediately make all articles about living people into ³stable versions,² editable only by administrators based on talk page consensus, so that we have at least some degree of control over what we say about people. We are doing way, way too much damage, and it has to stop, and stop now, before we really cause permanent harm to someone.
Are there less radical solutions that we have not tried out yet? Remember, we have MediaWiki:Sitenotice at our disposal to focus the attention of all registered users. We could have a global call to sign up for BLP patrol on Special:Recentchangeslinked/Category:Living_people -- make sure that hundreds of people look at the logs at least once per day.
I would not rule out more rigid application of semi-protection until we have revision tagging, but it seems like a poorly scalable solution. The problem certainly extends beyond BLPs to articles about high schools and universities, where teachers and professors are often targeted by drive-by idiots.