I've always found that a good heuristic for whose skateboarding deserves sponsorship is if you saw them skating in real life would they catch your attention? Would you stop and watch? Do they make you stoked? To bring in the aspect of sponsored female skateboarders I'd say most of them do interesting skateboarding that I would love to watch in real life. If I saw a girl doing anything sufficiently stylish or advanced to the point that they're special, I would be watching. If you can't see that Breana, a girl that kick flip manual impossible out with authority, is special, then you're lost.