The concept I have of a functional desktop is a follows.
Going to different work benches to focus on different tasks.
The current "workspaces" is a good foundation for this, but is insufficient. I visualize a clean desktop on which I might keep a few items handy (by having icons showing).
However I would like to have my "library" of frequently used tools/files at my fingertips. I remember "spatial placement" of items, so I would like to have those items remain in the location I assigned to them. More importantly, I would like those to be similarly to items on a bookcase, i.e. similar to seeing the spine on books. But in our case, I would like those books to be lying horizontally, stacked on one-another. Further, the bookcase would be like a wall unit, where you have multiple shelves (verticallly) and multiple racks (vertically).
The uploaded image portrays what I am visualizing as my "tool rack".
The number of shelves (vertical) and bookcases (horizontal) could be customizable.
Then, more importantly, this bookcase/tool-rack drops/pops down when clicking on the icon which would be visible on the panel.
The bookcase/tool-rack "overlay" would only cover 3/4 of the desktop, allowing some of the covered desktop to be exposed, so that you could drag an item from the desktop to be moved to the bookcase, or vice-versa.
I would see a different bookcase depending on which workspace is currently displayed (context-dependant). After all, you can't access physical bookcases when you are on the opposite side of the wall in another "work room", which is the paradigm that I am proposing be implemented.
The above summarizes my virtual implementation of my old desk which had a bookshelf installed on top of my desktop, for ready access of books, calculator, CDs, or other instruments for which I preferred ready-access, rather than go looking into different drawers.
Similarly, the desktop itself would be unique (context-dependant) to each workspace, NOT shared by all workspaces. Again the paradigm of going to a different workbench with a different set of tools and workspace layout, appropriate to the different uses for which each workspace is dedicated.
The existing panel app that is like a drop-down drawer does not take into account the human habit to physically place an item on a shelf, so that it may be later reclaimed from that same location.
I am REALLY hoping this kind of functionality can find its way into the desktop environment. With the trends to have all platforms behave the same, I am afraid that such a useful and practical paradigm will never find its way into reality.
My vision did not go 3D, because that is not how my mind works with the physical/visual/spatial placement of "objects". That doesn't mean that the concept could not be expanded to 3D, to emulate the stacks in a public or university library.
Here's hoping for the best ... and I will thank the developers in advance for making it happen.