First, site layout (top and left navigation bars, etc.) tends to be
impoverished, and more wiki-oriented than domain-oriented. Second,
if the organization changes regularly it can be difficult for repeat
users to find things. I hope maintainers will work to mitigate these
shortcomings, otherwise the result can be an unprofessional air of
"this is a development project which hasn't been around long enough
to develop a real web site".
I think some of your problems were actually addressed one my first post (or at least they should have been). By creating a hierarchy of the pages in the wiki it's possible to address your second objection with moving the site. Something like that ensures that only data relevant with a particular section is posted on that section, while still allowing others to modify it with current information. And keeping a standard format for these pages addresses the problem of the page looking different each time someone modifies it.
By the way, I'm new to the whole wiki modifying business, so I don't know the terminology!
Stefan