About this bad "jedi rocks" music, it's interesting to know what was the idea behind the other musical numbers we don't hate (I think):

-for the cantina band: imagine aliens from the future finding old records of early jazz of the 30's and trying to play these strange music with their future instruments and musical culture…

-for the tune "Jabba baroque recital" it's the same idea applied to baroque music (obviously)

In doth case the model is old enough in our culture the be beyond old fashion, if you take my meaning.

For a new music to replace "jedi rocks" one could follow the same reasoning, just a though…