Lemme know how it works out for you, but-- doing new things for new games, I'd recommend starting to consider other options. MediaWiki is a gargantuan and moderately filthy PHP app. Less awful than forums, but it is what it is.
Just as this forum software seems to be a better alternative to phpBB/SMF, there might well be (or should be) some shiny node.js based wiki system. Doing it with that would allow for future integration with node.js based MUservers, if such a thing ever comes to pass.