Philip Sandifer wrote:

Yes, the system is succeptible to the clueless and the crazy.

and

If we do not assume that our userbase is primarily comprised of reasonably competent people who will follow the principles described we are screwed.

I find these two statements to be in considerable tension with each other. The latter is not something I'm willing to assume, although it is certainly something we should strive toward. In fact, most of the community's social problems arise because people are too "clueless" or "crazy" to recognize the limits of their competence. We need to figure out how we can better push for more competent contributors.

Wikipedia's best contributors are those wise enough to know their own limitations. They hardly ever cause a stir because they don't overreach these limitations, or else they put the necessary effort into overcoming them. Unfortunately, far too many people lack either the self-awareness or self-control to respect their own limitations. That means we have to apply external controls. This may range from deleting content that is not helpful at all, to mercilessly editing poor-quality but salvageable content, to evicting contributors who are an overall detriment to the project. The proper uses of such remedies are tricky issues that require an abundance of good judgment. The community's ability to cope with that problem, the constant need for good and careful judgment, has not scaled very well.

--Michael Snow