I thought this would be kind of cool.
This would only function for sounds that do not have a 3D emitter, of course, but any sounds that are in a location where they directly play (i.e. PlayerGui or workspace) will have the option to both change the volume of the left/right channels, but also will have a modified form of PlaybackLoudness to show the loudness of left/right.
This would be beneficial because we could manually control 3D sounds for environments (Via “2D” sounds in the PlayerGui + manipulating the values), creating some really cool audio effects, i.e. a potion effect where the user can not hear correctly, so any sounds on the left speaker would play on the right, and visa-versa.
The #1 issue I see with this is with audio uploaded in Mono, or 3D audio sources. For mono audio, L/R could be mapped to the signal identically, and 3D audio sources could just ignore these factors (Or could use these factors to offset the sound)
We could also do stuff like this (THIS would be cool to do)