He neatly demonstrates some of the problems that WP has - VestedContributor and trusted reputation and a bunch of people circlejerking.
But, really, his damage is a minor problem that can be fixed with existing WP policies - check the fucking sources when you're promoting an article to good or whatever status.
What's worse is the way that WP deals with a slew of new users. Anon users (despite making most of the good edits on the site) are treated like shit. Registering a username is tricky with conflicting rules. Once you find you've broken a rule can very quickly find it escalating into a bunch of different warnings and blocks and harassment.
And don't get me started on the kids running around with auto-tools (twinkle, huggle, rollback, etc) making very rapid, but bad, decisions about other people's edits.
This is a more serious problem, and it's something that WP is only half-heartedly tackling.