1) Does not seem to work for applications with multiple windows
(you already know that per your comment in Launchpad)
I do know, and I haven't really come up with a good way to solve that. One of my main reasons to send this mail was actually to see if someone would bring that up and maybe propose a good way to solve it.
2) Even for applications with a single window, I believe cases
where users are not interested in such association are frequent.
Several users treat workspaces as extra space to be used as
needed (Gnome shell for example was designed with that
in mind) and not as fixed spaces.
I'm not sure I'm following you here. You say it's frequent for users not to want which association? You mean they don't want "four workspaces" but add and remove them as needed? If that's what you mean, I think Seb's idea addresses that gracefully, offering an easy way to add and remove additional workspaces right on the spot.
3) The size, and therefore easiness of interaction, of each
workspace is proportional to the number of itens inside it.
This makes switching to a specific workspace, literally, a
moving target.
True. I've made a second group of mockups, based on Seb's idea, which I think will solve that problem. Please take a look at them:
In the first mockup you see the situation with only one workspace: There are no empty workspaces, only the one being used (with firefox and hamster windows) and a second, empty one, which you can click or drag launchers to.
When you drag a launcher to that second workspace or navigate to it and open an app (in the second mockup I opened GIMP), a third, empty workspace appears which you can in turn navigate to.
Therefore, there is always one empty desktop (plus the ones that are in use). Never more, never less.
4) Disposing workspaces from a 2x2 grid in a linear stack makes
the association unnatural.
Might be... definitely not my opinion! Would like to hear if others agree, though.
5) In my opinion, the presentation as it is is not noticeable enough.
On the other hand, I cannot suggest anything more noticeable that
would not be excessively cluttered.
Maybe by taking some empty vertical space. Again, please see the new mockups. Following Seb's idea, I added an empty header to each workspace that could open its name (a la quicklist) when you hover over it, be clicked to move to it, clicked again to trigger expose, be grabbed to drag the workspace up or down (therefore changing its order) or be right-clicked to bring a quicklist with options.
Overall, in my opinion, the idea seems to add clutter and complexity
without bringing too many advantages.
Which problem, exactly, you are trying to solve?
