It would be very nice and handy to be able to add sounds to scenery objects - preferably in a way we do with f/e lights or we did with FX in FSX/P3D. The current system is limited to Simobjects which is more complicated and less versatile.
With MSFS, much more detailed models are possible including airport interiors. When visiting those, a good sound design would deepen the immersion even further but it is really tricky to do everything with simobjects.
So it would be ideal to be able to add an object like a bounding box (at particular coordinates in a scene), which would refer to a particular sound file. It should be possible to add multiple objects referred to the same sound file to cover a particular area - but even better - to be able to draw an area where a particular sound can be heard.
We can now f/e designate an exclude area for rain/snow (inside hangars/terminals) - a similar system but for enabling a particular sound file would be very nice in my opinion. So - just dropping an idea. The sound design in FS sceneries has never really been properly done although it may influence a feeling of a particular location a lot.