I would like to see a estate level tab set up that mimics the sound tab in the land settings. This would allow you to change the media settings for music across an entire estate at the same time. This would allow the changing of ambient music across several regions with out the use of scripts or hopping from sim to sim. Even in a modest estate of 12 sims checking all the music urls can be a issue.
One issue I can see with this type of request is some parcels on some estates should be exempt, like in rental sims. I would propose that there be a check mark at the parcel level that would exclude such changes, such as a setting check box that can be set by the tenet or others, maybe it would be a group ability to change this setting. An of course there would be a setting at the estate level that would exclude this ability.