A lot of people nowadays cite the loss of the 3 Ks as SW's downfall: Kershner & Kurtz for Jedi, Kasdan for the prequels. Kersh & Kurtz may well have made Jedi better, but there was talk at the time ('83) that Kasdan may have been part of the problem. After all, Jedi's script (Kasdan) was weaker than Empire's (Brackett & Kasdan), so, logically, Brackett was a genius and Kasdan a hack (at the time, Lucas was seen as infallible). Of course, history has shown that Lucas was probably the main culprit.