I was on a similar trail of thought, @manga ! I'd like to quote 'The League of Extraordinary Gentlemen' here... I don't have the exact quote, but basically, in the comic, when Hyde and Jekyll became different personalities, Jekyll began to get shorter while Hyde grew into a giant monster. Hyde says this is because "without Hyde, there is no one to drive Jekyll forward, and without Jekyll, there is no one holding Hyde back." In the Circle, "Gibra was our caution, holding us back." The members of the Circle were not balanced as individuals, they each had one purpose only (timekeeper, caution, passion...) but together, they formed a balanced entity.