I am looking to have control over what sort of compression an audio file is loaded at (from WWW), and whether it is imported as 3D sound, mono, etc. Basically, the stuff that can be done through AudioImporter or the Audio Import Settings.
The only difference is that this would need to be applied to audio files that are not known at compile time, and which are loaded via WWW. If I could even define the settings globally in Unity in advance (so that all files loaded through WWW are coming in with certain settings), that would also be workable. Right now it is noticeably degrading the quality of my stereo 192 kbps bitrate ogg files, though, which is making everything sound fairly muddy and muffled.
My sound designer and I are going to experiment with having a lower bitrate of 128 kbps and with a higher encoding quality, so maybe that will work, but it still seems like I ought to be able to make this work without having to modify files that play back perfectly well in other apps.