From my experience of looking at new, untaught users: their main problems are with understanding and having a grasp on what is what on the now common Windows/KDE/Xfce/IceWM-like desktop -- they get confused by the elements of the DE and afraid.
After thinking this over, I arrived at the conclusion that a Nextstep/WindowMaker/(perhaps Gnome 3)-like desktop is much more logical in its concepts, and simpler, and hence must be easier to understand for new users. So, I suggest a distro with a well set-up DE of this kind for users new to computers.
More details about the problem (as I see it) and the concerns I noticed:
to devise a more clear and convenient desktop environment for those users at home who can't grasp all the concepts of a usual modern complicated (= bloated) desktop environment (windows, window titlebars, minimized windows, applications in the tray) and hence can't keep track of the running applications and manage them efficiently.
(When I set up the system, I used to think that an XFCE would be a more or less acceptable choice (...), but I have noticed quite a lot of confusion. The problems:
(minor) The titlebar is not grasped as the control for the window (i.e., not part of the application, but a standard application-external control); rather, just it's just some confusing unpredictable text, even perhaps not associated with the window.
(minor) The usual application-specific menu at the top of the window is not seen/found (an application-specific menu is expected anywhere: in XFCE's elements, or deep inside the window).
(important) Taskbar does not give the needed information about the running applications (which might be in minimized windows): as I understand it, the rectangular regions with some text in them (the window titles) don't seem to be understandable, noticeable.
(related) Applications represented by icons in the tray only confuse things and exaggerate the problem with the taskbar: an application may be represented either there or here, no straightforward way to check all running applications.
Additionally, "simplified" window management means that there is no need to resize and move and fit windows, so something like a tiling window manager with one main large tile inside which the active window is always maximized can be thought of as an ideal (although, there are complications in practice: multi-window applications like Skype).
I thought of
either xmonad with one large main tile and all other windows represented by small (square) tiles aside--every running window is visible then and represented always the same way (no other representations: in the taskbar or in the tray); and very bold window decorations (so that windows are clear to be separate entities); and window-switching by selecting one of the small (square) tiles (wish: with the mouse); optionally: a window-switching layout (invoked with a simple key press, say, the Win or the Menu key), where all the windows are equal squares;
or WindowMaker--conceptually, the resulting solution will similar to the one with ''xmonad'' described above (but the single representation concept is broken: either a window or a big icon); a plus is that WindowMaker is a ready-to-use solution; some things will need to be tweaked: add an "applications" menu to the dock or another place, disallow window minimization (only iconification), try to make new windows maximized by default, make window maximization (or iconification if maximized?) the default action of a double-click on the title. (To distinguish this customization of WindowMaker from the standard one, I'll call it "automatic"--when a name is needed, e.g., in a pkg name.)
(What about Étoilé? GNUStep-based, similar to WindowMaker, but with a "global menu" (like in Mac OS). Is "global menu" more clear than per-window menu? Perhaps... But do distros support and care about Étoilé?..)
(What about Sugar? Can it be the base for a DE for grown-up, i.e., combined with the programs grown-ups use: the usual browser, mail client, OOo, etc.?)
With either solution, we will need to represent the files that previously (in XFCE) were on the desktop by a special invokable window (either a running file manager in xmonad, or a docked file-manager in WindowMaker). As for the file-manager choice, we'd better leave the tested and customized (as regards file associations) one from Xfce. (Or try the WindowMaker's one afresh? File associations could be not essential in WindowMaker, because one can drop the file onto the application in the dock, couldn't they?)
WindowMaker appears to have a very nice concept for non-professional users!
(Read some more bits of my elaboration on this topic...)