At the moment, our tree is in a "baby" state when it comes to first-level skills (I've already bashed "Technicals" numerous times!). It is far from exhaustive and accurate.
I would like your opinion on what the first-level skills should be.
Ideally, we should come up with a list of maximum 10-12 first-level skills. For simplicity sake, let's call the first-level skills, but they really are branches or categories that contain actual skills.
These first-level skills should be broad enough to contain every other skill. I am sure this has already been done a number of times, so maybe could just compare first-level categories in other classification systems.