bah. these rankings are just silly.
Universities are diverse. Some departments in a university are better than others. Perhaps having the rankings for certain disciplines makes more sense: i.e. psychology, physics, ancient history etc. But either way these rankings are based on rubbish. Who cares if the top CEO's comes from Harvard, what about the average student? And difficulty in getting in is based on peoples perception of certin university. USyd has the highest UAI requirement for psychology and subjects related to ancient history, yet they rank poorly compared to a number of universities in these areas.
Anyone who is concerned about these rankings actually meaning anything to most of us is worrying for nothing.