IMHO, the only legitimate points in this gentleman's post are: (1) a compromised browser defeats OAuth, and (2) OAuth isn't mobile-friendly because it requires browser interaction to gain user consent to grant access.
While both of these are true, Web browsers are ubiquitous; OAuth is a Web standard. You can abuse it slightly to make it work with mobile devices (see "access code grant") but really, it not was intended to be a be-all end-all authorization mechanism.
Likewise, claims that the protocol isn't "enterprise-friendly" are somewhat silly. OAuth was not intended for fine-grained authorization within an authentication or trust domain. It's for cross-domain (cross-application) grants, between unrelated apps, under the assumption that all three parties in the transaction are basically unrelated.
If an executive wants to delegate calendar permissions to his secretary, he should *just do it* by clicking a checkbox on Microsoft Outlook or whatever product they use for scheduling, which no doubt has its own rich permissions system and obviously has its own authentication mechanism. There's no need for a Web standard to facilitate this use case!
As for claims that "there is no standard" -- that's entirely true. There is a draft standard, which presumably will eventually be ratified by IETF once we have all had a chance to play with the technology and suggest improvements. Standards are not an item of worship; they're just a way to ensure that a protocol has had a reasonable degree of scrutiny, has no undisclosed patent encumbrances, etc. I've heard people accuse OAuth of being complex or flawed, but never fundametnally insecure.
Frankly, anyone who thinks the OAuth draft RFC is complex, should choose a dozen or so documents from the SAML protocol suite, relax in a hot bath, and read through several hundred pages of THAT claptrap. Then we can talk about complexity.
(Disclaimer: yes, I do read security standards in the bath, and I create toy implementations of security protocols and algorithms for fun. That probably makes me mentally ill.)