The SO Documentation format is highly tuned for the programming world. It's great for what it sets out to do (at least I think it will be), and some parts of it would be applicable to us — but using just parts of it as a way to organize documentation would set us on a course to walk all over Wikipedia and other sites. The difference between theology and programming is that Wikipedia only covers what things are, not how to use them with code samples and that turns out to be very useful in programming. There was a gap between Q&A and other extant documentation. That's what the void that SO Documentation aims to fill. I'm not sure there is such a gap for us, and if there is I'm not sure we should be filling it. The analog for us would not so much be documenting the beliefs of Christianity but giving examples of how to put those beliefs into practice.
In other words: becoming a full on self-help directory.
Lets wait (not that we have a choice, SE isn't actually offering the features to other sites yet and may never do so) and see how it plays out before we wring our hands to much over the possibilities.