Is the Windows task bar usable

You have that wrong. Open windows shoyuld not appear in the Dock because they already appear on the desktop -- the point is to have them appear in ONE location. Expose is not about making the windows appear in more than one place. it is about showing the windows in different ways. Nor is it fair to accuse Expose of being any kind of 'hack' -- it is built right into the OS, making it programming made by the product's real producer and requiring no interaction or customizing by the user.

What problem? A window that appears on the desktop does not need a representative icon in the Dock -- it is already available to the user. In other words, it might be different from what Windows does, but it still makes perfect sense and works to do the same thing (although the Expose functions are much better than anything I've seen in any other OS!)