After discussion at http://techblog.wikimedia.org/2009/04/planning-to-tighten-torblock-restrictions/ and http://lists.wikimedia.org/pipermail/wikitech-l/2009-April/042434.html , there's nearly unanimous agreement to change the configuration of the TorBlock extension to make it more strict.
I believe what's needed is to set:
$wgGroupPermissions['user']['torunblocked'] = true;
This change should probably be made concurrently with bug 18337 ("Enable "IP block exemption" on all Wikimedia wikis").
Version: unspecified
Severity: normal