So...as a beginning, I have reskinned the wiki. (If you want the old look, create an account and pick the old skin, called "monobook" in your preferences.) If you don't like the new look, you can send me a new style sheet or even an existing MediaWiki 1.9-compatible skin...I can install it and can select it in your preferences.
I have also installed some extensions that should help add additional flexibility (for example, the Wiki can now have image-based links). Over the next few days I will try to clean up the front page a bit to provide a clearer navigation structure.
One thing we will need on the Wiki is...WikiGnomes - that is, users who help to organize and polish the content for readability.
In the long term, I would like to migrate scenery.x-plane.com to the Wiki. But for now that is lower priority than creating new documentation.