With the exception of vector #6, this is pretty much a list of implementation flaws, not protocol flaws. It's as if he's trying to say that the protocol isn't written defensively enough or foolproof enough for implementors, and he might have a good point if he simply said that, but he never did.

Even with an OAuth library for the nuts and bolts, to implement an OAuth2 authorization server requires grokking the spec.

Vector #6 (Phishing by spoofed client) has always been particularly interesting to me, and it applies to both OAuth2 and OAuth1. I dont see it as a protocol flaw but an attack vector service providers need to be more aware of.

While OAuth2 was in draft, I reported it to Facebook, Google, Twitter and the OAuth WG. Facebook addressed it by displaying the domain name of the client on their authorization dialog, but they eventually got rid of that. Google also acknowledged the vulnerability and said they would rely on policing registered clients to catch it. Twitter never responded. The WG asked me to propose text for the security considerations document, but I dropped the ball (too swamped) and couldn't do it in time.