Van Der Hum
Agree totally with Arkady, you see nobody really knows what makes a controller tick. Selection purely on the basis of academic achievement has been found to be wanting, and Arkady's final para would serve both employer and potential employee alike.
Another solution would be to take this leviathon of complexity that is the UK ATC system and simplify it so that it can be performed by Joe Average and Norma Normal instead of having to become a four-dimensional chess player cum brain-warped psycho every time you plug the £10 headset into the billion dollar pile of computerised fish tanks.