Im not saying get rid of the existing ones, just to use the full musical palette that Williams has created over the years.
A lot of the Ep 4 music is pretty generic because it was first (It only really established a few motifs). Would be cool to have an alternate soundtrack that tied it all together better. Personally, I find the musical contrasts between the OT and PT among the most disorienting. The PT music is generally better, fuller and more musically interesting (as Williams had matured as a composer/musician).