I assume we would want CEV to exclude the preferences of sociopaths and psychopaths, as well as those of people who are actually mistaken about the beliefs underlying their preferences.

"Knew more, thought faster" should make the second irrelevant (and make the "theocracy" part of "xenophobic theocracy" implausible even given majority voting). The original CEV document actually opposed excluding anyone's preferences or loading the outcome in any way as an abuse of the programmers' power, but IIRC, Eliezer has made comments here indicating that he's backed down from that some.