I think the author's tirade against wikis is that many people use a wiki as a magical tool that allows them to forego writing documentation in the hopes it will suddenly appear, written by users that want to write documentation. This obviously isn't what typically happens.
However, I think wikis can be (and often are) a great format for documentation. The author(s) of the software should still be the primary and/or only contributors, but even so good wiki software serves to lower the barrier to writing documentation: creating/editing as simple as clicking edit, and you instantly see the results. You can link between pages, reducing duplication. Some software forces a hierarchy of pages, leading you to create things in a logical, structured way (of course, you can lead a horse to water...).
The key to this of course is that the person/people writing the software must write the bulk of the documentation (eg, like you would without the wiki as well). Don't allow random edits, or at least subject edits to a review process.If your project is big and successful, just as it lowers the barrier for you to write docs it may encourage others to contribute -- but don't rely on this.
Think of the wiki more like a publishing platform or format; not like a way to absolve yourself of the responsibility to write documentation.