I've installed the wikitools module so now wiki style links will find existing pages. This module also enforces unique page names, I'm not sure if this just applies to the wiki or if it has an effect on the rest of the site. If there are existing pages with clashing names then they will complain when they are edited and will not allow changes to be saved unless they are renamed.

Depending on what presentation style we are looking for then the PEAR Wiki Filter module might be interesting. This would allow the wiki to work in a similar way to a number of popular wiki formats. This would also depend on the PEAR Text_Wiki package. An alternative would be using the flexifilter module.