I think it is fairly low risk to post to the Universities to Fear wiki for a couple of reasons. First, if you post now, before they make an offer and before someone accepts, they will have much less of an idea of who might have posted (I assume, that they would assume, that it is not the person who accepted an offer from them). Second, no one in that department may be aware of this particular wiki - I know I wasn't until a few years ago, a few years post-successful search. When I asked colleagues in my department, many were not aware that such a site existed.
You could always wait until next year, particularly if they have another search next year (which, one might reasonably conclude is of some potential, though not a guarantee) if other interviewees had experiences similar to the one you had.
All that said, if you do decide to post, if you present a balanced view as possible of pros and cons, and avoid coming across as more of a "rant", you run much less risk of blow back.
But, balancing these thoughts out - assuming they had 3 on-site interviews, they have a fairly narrow range of individuals who might have posted to pick from (even fewer if you wait to post until after they make an offer/fill the position). As such, I don't think there is anything you can do to completely eliminate the possibility of them identifying you (or, strongly suspecting you).