I suppose the major obstacle would be the difficulty in dealing with audio hardware specific stuff on different platforms. If only there was a multi-platform open language for audio support like openGl for graphics. Shame, it would be great

It would make gE a completely self sufficient game creation tool. Artwork & widgets with Canvas actors, music & sound effects with Sound actors. All you would need is gE. No need for library of sounds, images with all the copyright issuses because you create your own or those released on the forums for community consumption (all created with gE itself). How cool would that be? It's asking for a lot. Still a cool thing if EVER possible (although doubt it). What a challenage for the Dev team this would be?