Oh, but it would. It would just not be called PulseAudio. Instead, every part that has to do with audio implements largely the same functionality, and hits the same problems as PA did. Instead of being able to point to PA for making sound crap, you can now say that *everything* is crap.
Would it do this?
http://www.allegro.cc/forums/thread/600325
Taking over the devices is a BAD IDEA. Providing a separate mechanism to provide the audio switching functionality is a much better idea.
I'm calling for the Bluetooth drivers to provide the Bluetooth audio switching functionality.