He is obviously PhD-level bright and probably quite a bit above average PhD-holder level. He writes well, he has learned quite a lot of cognitive science and I think that writing a thesis would be expenditure of diligence and time more than effort for him.
From the other point of view, some of his writings make me think that he doesn't have the feel of, for example, what is possible and what is not with programming due to relatively limited practice. This also makes me heavily discount his position on FOOM when it clashes with the predictions of people from the field and with predictions of, say, Jeff Hawkins who studied both AI sciences and neurology and Hanson's economical arguments at the same time.
It feels to me that he skipped all the fundamentals and everything not immediately rewarding when he taught himself.
The AI position is kind of bizarre. I know that people whom themselves have some sort of ability gap when it comes to innovation - similar to lack of mental visualization capability but for innovation - they assume that all innovation is done by straightforward serial process (the kind that can be very much speed up on computer), similar to how people whom can't mentally visualize assume that the tasks done using mental imagery are done with...
I've spent so much time in the cogsci literature that I know the LW approach to rationality is basically the mainstream cogsci approach to rationality (plus some extra stuff about, e.g., language), but... do other people not know this? Do people one step removed from LessWrong — say, in the 'atheist' and 'skeptic' communities — not know this? If this is causing credibility problems in our broader community, it'd be relatively easy to show people that Less Wrong is not, in fact, a "fringe" approach to rationality.
For example, here's Oaksford & Chater in the second chapter to the (excellent) new Oxford Handbook of Thinking and Reasoning, the one on normative systems of rationality:
Is it meaningful to attempt to develop a general theory of rationality at all? We might tentatively suggest that it is a prima facie sign of irrationality to believe in alien abduction, or to will a sports team to win in order to increase their chance of victory. But these views or actions might be entirely rational, given suitably nonstandard background beliefs about other alien activity and the general efficacy of psychic powers. Irrationality may, though, be ascribed if there is a clash between a particular belief or behavior and such background assumptions. Thus, a thorough-going physicalist may, perhaps, be accused of irrationality if she simultaneously believes in psychic powers. A theory of rationality cannot, therefore, be viewed as clarifying either what people should believe or how people should act—but it can determine whether beliefs and behaviors are compatible. Similarly, a theory of rational choice cannot determine whether it is rational to smoke or to exercise daily; but it might clarify whether a particular choice is compatible with other beliefs and choices.
From this viewpoint, normative theories can be viewed as clarifying conditions of consistency… Logic can be viewed as studying the notion of consistency over beliefs. Probability… studies consistency over degrees of belief. Rational choice theory studies the consistency of beliefs and values with choices.
They go on to clarify that by probability they mean Bayesian probability theory, and by rational choice theory they mean Bayesian decision theory. You'll get the same account in the textbooks on the cogsci of rationality, e.g. Thinking and Deciding or Rational Choice in an Uncertain World.