While I usually would say the same, as I understood pipewire they are trying to create a unifying abstraction layer with a stable API that handles the underlying cruft.

While I would have wished for a good clean solution from the start, the state of the current Linux Audio stack doesn't IMO really allow for such a solution without breaking every program ever.

If Linux Audio needs one thing it would be something that handles the weird relationships between ALSA/Pulseaudio/Jack in a clear and automatic fashion. Because as for now I have seen Linux Sysadmins with 30 years of experience tear their hair out because they couldn't wrap their head around Linux Audio.

Build a blackbox around it and try to rework it on the inside.

I'm not sure what you mean. Pipewire goes out of its way to have ABI compatibility, so all your old applications using Pulse/Jack will just work.

What about ALSA or OSS applications?

I believe there is a pipewire ALSA module, and for OSS there are (were?) numerous ways to get that emulated in ALSA.

Ok so it should not be worse than pre-PipeWire at least. Too bad Linux can't just make /dev/dsp be usable by multiple applications like the *BSDs managed.