Noticing the comment about "development," I have my two cents to add:
If you think code (other than short snippets illustrating how to do something) should be posted on a wiki or anything like that, I don't think it's a very good idea at all. Ideally, code that is going to be a sort of community project (any significant amount, like a whole file) should be posted on SVN or some other kind of version control system. These systems are much more suited to programmers.
With regards to making the website a wiki, my opinion is a big resounding "no." In my opinion, the website is best meant as a place to put pages and information that changes infrequently (such as the IRC / hamachi setup guides, download pages, links pages, etc). Stuff like this, help file contents, etc. shouldn't be posted on a wiki (this kind of information has no real reason to be changed often and a wiki encourages that to a point).
I think the biggest barrier to having a maintainable wiki, however, is the lack of manpower we need to keep it organized. Ideally, there should be editors who periodically clean up, revise, etc. If we can't get people who will periodically devote time to this, we shouldn't have a wiki. (And the excuse that "allowing the whole community to edit" doesn't really seem to work either. Large wikis like Wikipedia still have groups of editors, admins, etc. who go through and clean up the garbage. If we make the wiki a free-for-all then all kinds of useless crap is bound to get posted just like what we have now).
Another thing is the software used. The current software we use (mediawiki) is terrible to upkeep and maintain, and I have heard many a complaint about the terrible wiki syntax it uses. In my opinion a good wiki would either: a) have a graphical / wysiwyg editor, or B) allow a subset of HTML so that people can use what they are familiar with, rather than having to learn some new, useless markup language to write pages for the Wiki.