I wanted to hear a new main title theme, to differentiate the PT from the OT and to maintain the integrity of the Main Titles as Luke's Theme. Imagine, ten years from now, some kid watches the PT and kind of likes it. Then he puts in Episode IV, hears a completely new, bombastic, exciting score and reads the words, "A New Hope." That could've been awesome.
What would you want it to sound like? Can you think of any other movie themes you'd compare it to?