The arXiv paper indicates he has no intention of submitting it to a peer-reviewed journal -- something that's becoming pretty common in some physics fields. On the contrary, I see the "yet to pass peer review" remark as a crass editorialization from the Nature journalists¹. This paper has already seen more, meaningful, peer review that most papers Nature publishes; informal review from people downloading the (free, open) paper from the arXiv, or listening to the talk at the Kavli conference. The institute Nature is defending is becoming an irrelevant middleman: what's the point of reviewers, if they barely read the papers, and then hide them behind paywalls from anyone who actually wants to read them, when there's whole social network of researchers who will read papers enthusiastically, for free, and share what they think of them?

http://arxiv.org/abs/1401.5761

¹ You should question to what extent they're journalists, when their employer is a for-profit entity existentially threatened by the subject they're reporting on.