I recently floated the idea of morphing the real-names requirement into a registration requirement — you’d have to sign in with WordPress, Twitter, Google Plus or Facebook, which meant that you’d be posting under a verified identity but not necessarily a real name.
I’ve decided to leave things alone, at least for the time being. A few people really think the real-names requirement is something I ought to keep. And if I’m going to do that, then there’s no reason to require registration with a third-party service.
If WordPress.com ever makes it possible to add a service like Disqus or Open ID, I may revisit the issue. For now, those services can only be used with hosted blogs using WordPress.org.