If it does go to court and their case stands up (and the idea of an anonymous wiki with no personal responsibility does not feature in most defamation laws), it could be the end of the wiki, or at least of the pseudonymously editable one. Wikipedia could continue on either being moderated or requiring all contributors to have verified identities kept on file and assume legal liability for their edits. Which would be somewhat of a chilling effect, though it could be argued that that's how the real world works, and the present Wikipedia is no more legally sustainable than the original Napster was. And so, another piece of the utopian anarchy of the internet (you know, that ungoverned interzone that interprets censorship as damage and routes around it) may soon fall to the encroaching tide of harsh reality.
Update: I have been informed that any such lawsuit would be a non-starter. For one, one cannot legally libel, slander or defame a deceased person, and secondly, the Scientologists have already tried this sort of thing and failed.