Check out this article by Geoffrey Stone on judicial selection in the United States. Stone is arguing in the context of the American Constitution but the general points are still applicable to the South African constitution and judiciary. The article gives a decent outline about why the type of judges we appoint matters. What the Constitution and the law requires is not only a matter of application. Judges also engage in extensive moral and political reasoning. So, the moral and political philosophies of our judges can be an important determinant of the outcome of cases (particularly the cases that reach the SCA and Con Court).