I support use of a wiki too. At least if I contribute something I will be able to see the results straight away.
As with the current method, I submitted a docbook file containing some updated problem sets to OpenACS a while back. However I don't think it was included as part of the documentation, or it was and I just can't find it. :) I found that a bit annoying, and have been a bit slack on contributing more documentation as a result.
The only problem I have with a wiki is what if someone wants to print out the documentation? Should the wiki some how collate all pages into one long printer friendly page that can be printed?
The way I see it, docbook gives us more freedom on how to present the documentation. However it makes contributing documentation a little more painful by having to setup docbook and learn a new markup. A wiki provides fewer barriers of entry for contributors, but it means all documentation is stored within the database making it trickier to print the docs as a book.
