David Gerard:
We're having fun with this on [[WP:SCN]] (a Scientology wikiproject). You have the views of the CoS members and the views of the critics, and they're basically almost utterly incompatible. But NPOV is achievable! With great effort! (Also, we have a recently ex-member who's doing a great job on the articles about the "tech", i.e. the substance of the religion itself.) [[Xenu]] is achieving widespread fame in the blogosphere, and is being quoted (uncredited) in just about every recent press article on Tom Cruise's proselytisation for the Church. So we're getting just a little attention. I'm sure we'll weather it, and Wikipedia's immune systems appear to be kicking in just fine in at least one case ...
While I would love to agree with you entirely, the situation e.g. with the LDS articles is exactly the opposite. Criticism is spread on sub-articles of sub-articles, and you have pages like http://en.wikipedia.org/wiki/Anti-Mormonism which is largely an LDS description of anti-Mormon activities. Some of the LDS pages could come straight out of glossy brochures from Utah.
Then you have stuff like http://en.wikipedia.org/wiki/Nephi - a character out of the Book of Mormon - which is simply prefaced with "According to the Book of Mormon", and everything else is presented as fact. There's a Mormonism WikiProject: http://en.wikipedia.org/wiki/Wikipedia:WikiProject_Latter_Day_Saint_movement - most of whose members appear to be Mormons.
There are many passionate Mormons and relatively few critics. The critics focus on a small number of key articles, which are continually unstable. Many articles off the main center of activity will simply reflect official LDS or at least believer POV because nobody else cares to work on them, and even if they do, they can easily be pushed away by the Mormon majority.
Opus Dei members are also presently trying to turn the OD-related articles into pure apologetics, largely relying on writings by Catholic scholars and trying to discredit everyone in the anti-cult movement outside the Church. In addition to changing the text, some of them tried to insert series of photos of smiling women and children into the main article to reflect the "theology of joy" of Opus Dei. This effort is currently stalled due to copyright issues with the images.
Then there's articles like [[creationism]] which never reach any level of long-term stability, and where, beyond the conflict between science and faith, there's a conflict between many different beliefs about creation, Christian or otherwise, and whether or not they should challenge science, or coexist with it.
Every religious movement with resources and some intelligence will eventually discover Wikipedia and try to systematically undermine its articles, aided by the passion of its members. If we want to stay open even to irrationalism, there is no solution beyond occasionally taking snapshots when the articles have reached some level of stability. That is, when we have peer review, we can systematically try to guide NPOV-aware Wikipedians into the dark corners of Wikipedia and push them to be ready for publication, then leave them to the ignor^Wpeople of faith again.
Erik