@jdnicoll a similar mechanic is the Wild Die from the D6 System #OpenD6 #D6System #StarWarsD6 #OpenSource #OGL
http://opend6project.org/section-4-game-basics/making-actions/

This lets them be 2D or so in most attributes, and make up the difference with skill training, but be 6D in their best. #StarWars #D6system #d6Space