The problem with the openal32.dll -> libopenal.so wrapper was that it broke some games, and we never debugged why. If anyone wants to continue this development I think this wrapper library is something that would be highly welcome.
As for the winmm driver, Roderick pretty much said it. We don't need another half baked sound backend, the effort should instead be put into making sure we have one properly working one for each platform(Alsa for Linux, coreaudio on the mac, not sure about *BSD and Solaris)
