This has been brought up before, and it's quite a bit of work. You can't just simply forward everything to pulse call it a day, you'd need to implement a full structure/drivers/etc., which would require quite a bit of time/work and is likely outside of the scope of 1.0.
And I believe Julliard rejected the idea of adding a pulseaudio driver.
Nope! He isn't against a pulseaudio driver. He is against yet another broken and half implemented driver for the desktop sound system that happens to be en vogue at the moment.
I think he would love to see a clean, full implemented pulseaudio driver; presented in a nice easy review-able patch series which cleans up the wineaudio driver mess en passant.
"No, the right answer is to make the Alsa driver work right. We need to stop rushing out to write a new driver every time there's a problem with an existing one, all it leads to is more broken drivers." -Julliard
http://winehq.org/pipermail/wine-devel/2008-March/063755.html
... I also guess no one is stopping people from writing a pulseaudio driver.
Its just that it needs to make certain criteria before inclusion, after we got burned with esound, arts, nas, etc etc etc etc.
Ciao, Marcus