In short, he generally does not get credit for what he knows and understands because he cannot communicate clearly with people who do not already know and understand his philosophy.
Said another way, if you can't explain things to people unless they already understand you, then you can't explain things to people.
His AI arguments seem to be of the "If you assume an AGI singularity is possible..." kind, which is suspiciously like assuming god exists, for completely arbitrary values of god, and then debating whether or not he cares enough to hate you.
Most software today sucks so badly it can't tie its own shoelaces without poking itself in the brain and falling over.
How do we know this isn't a general feature of software? Has there ever been a 100% bullet-proof non-trivial software system? Is there anything in the history of CS which implies that such a system is possible?
So suggesting that by (say) 2066 software will not only stop sucking but will be able to meta-improve itself with bug-free perfection to the point where it can eat the world seems curiously ungrounded.
Now, maybe it's possible that a task-oriented AI will at some point develop a personality. But there is no evidence that such a thing is possible.
The "real life" personalities we observe in nature--ourselves--did not evolve from task-oriented machinery. It was the opposite: personality and will is observable in even simple animals; a beetle directs its own actions and tries above all else to preserve its own life. No one sets a task for it.
Where does a beetle get that self-direction? Well, what is life itself? Where did it come from? We find ourselves in very deep waters; the depths of which I think AI-fearing folks don't seem to appreciate.
That's a straw man. Software doesn't need to be bug-free to take over the world, literally or figuratively. Cars replaced horses but weren't fault-free. PCs replaced typewriters but weren't bug-free. All software needs to do to take over the world is be sufficiently competent and superior to its competitors - products or (in the case he's concerned about) humans.
Also, it's true that one AI might blow itself up, or make a fatal mistake, while trying to take over the world, but it only needs one idiot misconfiguring his AI in his basement to give us a potential world-destroying calamity - the classic "paperclip-maximiser" problem. That's a very hard problem, and it's bigger than solving the AI control problem - it's no good knowing the secret to keeping AIs under control with probability 0.9999999999999999... if someone else unleashes a dangerous AI without knowing that secret, or deliberately ignores it due to insanity or some death-wish on humanity.
And while he doesn't focus on this, there are plenty of AI risks that we still might conceivably face even if we defeat the outright existential risks, the threats to our very existence as a species. For example, consider what would happen if a paedophile or a rapist got hold of a very powerful AI and was able to command it...
Go through his non-philosophical papers and point to one thing in there that's brilliant. His miniscule technical output also seems to agree with this.
I weep for the world that considers people like Yudkowsky brilliant.
The easiest example of his work that I'd describe as brilliant is HPMOR. It is a story that makes the Harry Potter world not just bearable but beautiful and lively. There are portions where the philosophy comes on so thick as to disrupt the story, but on the whole it is a beautiful work. Reading it is how I first discovered EY.
Gwern, Hal Finny, Wei Dai, Hannu Rajaniemi, Aaron Swartz, and Scott Alexander are some of the more well-known (outside of LessWrong) former members. It really was an interesting community for a while. There were meet-ups and Yudkowsky did solicit for his nonprofit, but it never seemed culty to me. And none of the people I mentioned ever seemed wary of criticizing Yudkowsky when they thought he was wrong. See, for example, Gwern's epic reply to Yudkowsky's post on automation: http://lesswrong.com/lw/hh4/the_robots_ai_and_unemployment_a...
This doesn't seem like the type of reply an entranced follower would give their guru. The fact that this very-critical comment got twice as many upvotes as the original post is telling of the attitude of the community as a whole.