I believe it makes sense for wine to keep the oss and alsa drivers as low level as possible for users that require performance over useability. The straight to hardware philosophy of direct sound should be honored when possible. This would be appropriate for games, voip or low latency music applications.
ALSA is designed to avoid this sort of dichotomy. It does not matter to the app whether it opens "hw:0" or "plughw:0" or "plug:dmix:0" - the same code is used in every case. The fact that each of these virtual devices has quite different operating characteristics should be of interest to the user, but not to the code.
There are places where this doesn't work. alsa-devel wants to hear about them, and plans to fix them.
If usability rather than performance (as in multiple applications) is important, then higher level drivers like jack or arts should be used.
JACK is not aimed at usability, but performance. It enforces timing constraints rather than leaving it to a bunch of hapless apps to mess it up. You cannot hope to use JACK within Wine without intermediate buffering, which actually makes using JACK somewhat pointless. I say somewhat only because it still permits device sharing, but at the cost of losing sample accurate synchronization.
--p