Plans to introduce a filter so that legacy JetPack [audio] playlists will work again?
Since WordPress Core now includes its own Audio player, I think it would make more sense to improve the core Audio player to handle playlists. But until then, I agree that it would be nice to find a way to fall back to Jetpack's audio player for playlists. I created a trac ticket about this, and we'll work on it:
http://plugins.trac.wordpress.org/ticket/1869