Hey Darik,
the Skills page doesn't list magical skills because we figured people wouldn't want to see magic mixed with "regular" skills (we did include links to the relevant pages, though). On the other hand, Category:Skills is an automatically generated page. Any page with the declaration [[Category:Skills]] in it will show up there, and that line is included in the Skilltree template, so basically any page with a skill tree (the colored table with proficiency levels and descriptions) goes in that category.
We are open to suggestions for improvement, though.
Please remember that you need your wiki account added to the Contributors group before you can edit the wiki. Let me know if I have to do that for you!