The OS9.1 implementation is certainly an improvement - the windows menu has been a feature of Internet Explorer, Photoshop and Illustrator for a while now and is invaluable.
As for Rene's comment, I agree: I think for most work, we will be living in one Finder window - barring file or alias drag-copying. But the single window finder will not solve another major concern which is that doc windows from any app can become interleaved with windows from other apps and the finder... a behaviour you see on the PC. I can foresee this becoming extremely confusing, irrespective of whether you can windowshade or minimise to the dock. What might help is a "doc dock" - a totally seperate dock for documents only. It's not uncommon to have over twenty windows open at once and the dock is not enough in such cases. Do we really have to run a seperate window manager app when such functionality could easily be built into the OS?
Frankly, I would like to hear any suggestions why windows do interleave. If I'm running Photoshop, I generally want to keep all the Pshop windows together. They could potentially get jumbled up with all the other windows. I admit that I haven't used the beta enough in a real-world context to discover if the advantages outweigh the confusion... Anyone think different? Either way, some method of quickly navigating open windows is needed and the dock, as it stands, is not enough - if you can't visually identify the document, you are forced to "scrub" over all the docs until the name of the one you want appears. A solution more akin to the Photoshop Layers pallette would be more appropriate - name AND iconic representation...
On reflection, we may find that windowshade becomes less important - let me explain. We conventionally use WS to "peep" behind an open window. The alternative - dragging the window - is longwinded. First, click on title bar... start to drag (outline of window moves with mouse)... release mouse... window skips to new position... finally revealing window beneath. Now that windows move in realtime, it more closely resembles the action of sliding a piece of paper out of the way. That doesn't mean we shouldn't have the standard window shade action though!