Bearing in mind that I've never had any problems with regular discussions or conversations, even amongst the few (the proud few) that I've had to infract upon, let's just set that aside and accept that some individuals may be intimidated in any discussion with a mod no matter how banal. So, if there are people out there that actively fear (or at least censor themselves because of) moderation, wouldn't Ledgem's proposal just create a sleeper agent scenario where everyone distrusts each other because anyone could be a moderator in disguise? Personally, I greatly dislike the thought that I could be bad mouthing a mod to a friend only to find out later that they were also a mod.
Additionally, the added layer of anonymity seems a little silly. We are not super heroes. We do not need to wear a(n extra) mask in order to protect ourselves, families and friends. There is already enough distance created via usernames and avatars that extending it further to our very activities seems not only disingenuous but down right mean (to the posters). Everyone deserves a chance to confront the person bringing charges against them (though not necessarily the person leveling the charges in the first place).
Also, it is really hard to write in other characters voices (especially if you are switching back and forth frequently). Would all of Monir's secret identity posts suddenly be uber serious lacking any of his wit
or charm 
? Would Hunter's secret identity posts be bubbly and super fun? Would Relentlessness' posts contain only one sentence texts that have little bearing on the discussion at hand? Would I have to give up my parentheses and ellipses? No, "regular" posters would be able to figure out who we are fairly easily, to the point where the secret identity becomes meaningless.
(And this isn't even getting into the issue of rigging the polls and other issues dealing with having the ability to post twice under a different name. All of which are reasons why we prevent others from having duplicate accounts.)
What little intimidation or disconnect may exist due to our bolded names and little moderator tag is not worth the hassle of a duplicate account, especially since we can retire at any time (and change our names in the process).
edit: Don't think of this as the official moderator stance on this issue. This is my personal stance first and foremost.
edit 2: It seems much of what I have written has been touched upon by other posters whilst I was writing. C'est la vie...