During progression of the Shadowbringers MSQ, the music for certain zones will change with no way to change it back, which is unfortunate for people who prefer the original themes over the newer ones. While getting Orchestrion rolls for the old themes would be fantastic, I would love it if we had the option to have them back in the zones themselves as well.

My suggestion is to maybe implement an NPC (a bard perhaps, with the implication that they're playing the background music and all that) in each of the applicable zones (or put one in either of the hub areas). They could appear after completion of the Main Scenario and when spoken to, offer a line or two of dialogue about what they're doing then ask the player if there is something in particular they'd like to hear :
  • "Play me something nostalgic/somber." (Old theme)
  • "Play me something uplifting/cheery." (New/current theme)

Something along the lines of that, maybe? Thought it might be a neat idea.
Either way please SE let me listen to the old stuff again!