A mixture of skill, creativity, personal responsibility, knowledge, and perhaps their behaviour/admins words.
I think it's too much of a popularity contest to go with voting, too constricting to say admin choice only, too ~ for fight to the death (videogame skills aren't the only thing)...
It's obviously something that needs more of a peeking into
As long as whoever is chosen isn't a Naruto Clone, a Sasuke Clone, Orochimaru Clone, or some twit who has no creativity I'd be happy. I just don't want my Kage- who us intense RP'ers will have to participate with- to be horribad.