With the 3D dock it reminds me of the early 90's, when operating systems were starting to be designed with real-world metaphors.
Dragging something to the recycle bin was as arduous a process as it was in real life - it was much easier to hit the delete key. So, with the dock they are doing it again, emphasising that shelf metaphor (with it now looking 3D, rather than a UI element) and I don't think it's positive step.
A computer is a computer, a desk is a desk.