See - I don't think tight playlists works for some formats. Yes, it works for top 40 formats - After all, that is what top 40 is but you go try to pull some top 40 over played small playlist on an alternative or classic rock format, you are going to lose listeners. Classic Hits is a different situation because it focuses on the hits (hence it's name). Good Classic Rock stations though like KZ 106 in Chattanooga and KSHE 95 in St. Louis do NOT have small playlists and have amazing ratings.
Power, Star, Q100, and even pop country stations can play that limited playlist where you hear the same song every 75 minutes but you go pull that on a classic rock, AAA, and Alternative, you will get a backlash. Go check out the facebook page comments on X107.1 (Alt40 format) and you will see what I mean.