I doubt its really all that necessary at this point in time, and can only see it raising mobo prices and creating a rift in the soundcard market. You would then have PCI and whatever this new type of card. I have an audigy 2, and the sound is perfect.
Besides, with PCI express coming as fast as it is, it won't be long before PCI is outdated anyways, and the new soundcards would just work with the new PCI slots, nuff said.