The typical student Yale searches for shows excellence, potential and are hungry learners. Often, that can be bundled under typical "type A" traits (leadership, social skills, somewhat competitive, outgoing, driven). But unique talents also can be highly valued.
Being passive, lacking superior drive/ambition, indecisive -- aren't traits that will show well for a school like Yale.
Yale definitely nurtures future leaders/innovators. Yalies also tend to learn great group dynamic skills too. I tend to believe that coopertative skills are highly valued in this sub group too. In that case -- I think others benefit.