Browsers have made important GUI progress in terms of usability and minimalism - I think some can be copied into dekstops.
1. Opening and closing application can intuitively take place in the same bar. The 'plus' (Firefox new tab) button can be located in the task bar and receive most of the 'Lubuntu start menu' functionality (open new programs, install and unistall etc.) A close button can be placed on the 'tab' as is done in Firefox.
2. Apps can be fixed in your taskbar or "application launch bar" in a similar way as pinning a tab in Firefox.
3. The "Lubuntu start menu button" can give access to a preferences/settings/search pane.
4. A 'reveal desktop' button should become default ('minimalising' all)
This could clear up a lot of the space taken up by each window as we no longer require a bar on top of each window for either the title and a close button. The minimalisation button could be replaced with 'clicking' on the tab an extra time.
Also I think this makes the whole process of launching/closing and installing programs.
See attached concept.
However, the maximalisation button poses some problems. Completely copying the Firefox tabs system implies that windows are always full-screen and, hence, complicates people's custom to resizing windows and seeing a desktop behind their windows. In Firefox a separate 'window' can be created by clicking on a tab and dragging it down. This is possible here as well, but how can one 'localise' this window if it disappears from the taskbar!? Alternatives:
A). A non full-screen window is no longer possible
B). A resized window remains in the taskbar, but maybe in an alternative space (say on the right of a line) in the taskbar; or a 'higher level' taskbar should appear.