I honestly don't like mod applications. I notice that forums who take 'em usually end up with a large amount of staff; more than I usually think is necessary. It's a lot nicer to be picked for the position than applying for it and being chosen imho... that and, as stated, opening up apps will likely attract people who are just applying because they want to be staff since they'll see it as an opportunity. x_o; H-Staff and above choosing mods is one of the nice things about PC, keeps everything quality and doesn't let the staff team get bigger than it needs to be. Better to look through candidates that don't directly apply for the position, since an application changes everything. People lie, type differently than they would, and so on.
Though I'm sure there's lots of people here who would do an amazing job moderating sections, there really isn't a need for a new moderator for a lot of them at the 'mo, I think. If they're dedicated enough, they'll get their chance to help out without that fancy bold blue!
It'd be cool to give it a test run in the future though~ n__n Sure it won't hurt to try, though it likely won't happen (in the near future), I think. PC already chooses great mods using their current method.