As for his expertise on theology, or lack thereof, I know he's said something to the effect of, "Does someone have to be an expert on leprachaunology to say that leprechauns don't exist?" My response, I think, would be maybe not, but if you feel the topic is worth writing a book on, some background would be helpful. Frankly, and I mean no disrespect, I think the rationale you and Dawkins use to justify not addressing legitimate theology is a bit of a cop-out, and it's also fallacious in that it's an argument from your conclusion ("There can be no legitimate case made for the existence of God, therefore no case made for the existence of God should be considered or addressed.")
But he's been criticized for much more than just that. Many of his atheist colleagues think he's resorted to what you acknowledge as shock tactics instead of raising legitimate objections. I.e., he uses a lot of straw men.
He's also caught a lot of flak (again, from atheists) for being very selective with his "evidence." He addresses all of the evils done by religion without acknowledging any of the good, and does just the opposite for atheistic systems. Additionally, it may be worth mentioning that such anecdotal evidence doesn't establish a causal relationship in any event.
Finally, you say that you think anyone who is "anything except a very skeptical agnostic is pretty stupid." I doubt Dawkins would consider himself agnostic at all; he's an avowed atheist. Do you mean to say, "Anyone who accepts that there is anything more than a slim chance that God exists is pretty stupid"? Or would you include atheists in your dismissal of any viewpoints other than agnosticism?