This strikes me as wrong. The proper work of philosophers and computer scientists seem like they have very little overlap. Yes, philosophers often mistakenly do computer science work, but that is irrelevant.

The quote isn't talking about philosophy in general, but epistemology specifically. If you take naturalized epistemology seriously (which LessWrongers do), then it seems to follow quite easily that neuroscientists and AI researchers are relatively more important to the future of epistemology than philosophers (remember that most branches of modern science were once a part of philosophy, but later broke off and developed their own class of domain specialists).

is there a reason I should want to read an earlier, less developed version of LessWrong, by someone who is not a consequentialist, when I could just read LessWrong?

One reason to read it would be to provide ourselves with some perspective on how LessWrongism fits into the larger Western intellectual tradition. Nozick is much better about showing how his ideas are related to those of other thinkers than the contributors to Less Wrong are (we share much more in common with Wittgenstein, Quine, Hempel, and Bridgeman than the impression you would get from reading the Sequences). Having this perspective should increase our ability to communicate effectively with other intellectual communities.

His being or not being a consequentialist doesn't seem to have very much to do with the validity of his work in epistemology, decision theory, philosophy of science, or metaphysics. Also, his ethical theory doesn't really fit neatly into the deontological/consequentialism dichotomy anyway. Arguably his ethics/political theory amounts to consequentialism with "side-constraints" (that can even be violated in extreme circumstances). It doesn't seem to be any less consequentislist than, say, rule-utilitarianism.