This is an interesting analysis and I can think of two opposing scenarios that might both be important (note that this is purely speculation based on observing

This is an interesting analysis and I can think of two opposing scenarios that might both be important (note that this is purely speculation based on observing people in industry): 1) Having more full professors might indicate a strength in the core math and theories behind CS. This field is much slower moving than the "technology du jour", so continuity and continued thought is important. 2) Associate and assistant professors (in theory younger and more attuned to the latest technology fads) might be what ties the almost real-time advances to the backing theories. If my hypothesis holds true (and I have no data that proves it does), then balanced CS departments would be most effective. Many times having a broader demographic is advantageous, so this shouldn't be a surprise.