Binary package hint: compiz
The default Alt+Tab switcher ("Application Switcher") in Ubuntu/compiz is badly designed from a usability point of view, and differs from the alt-tab in metacity. Since the application swticher is a default feature and fundamental feature of the desktop, I think this issue is important.
In metacity: when you alt+tab, previews of all windows are shown at once, if necessary organised into multiple rows and shrunk to fit them all on screen. The window previews stay in a fixed position, and as you press Tab the highlight moves from one to the next. Because the windows stay still and the selection moves it is easy to spot the window you are moving to and to judge how far you are from it, and know when you have arrived at it. Also, you immediately understand how many windows there are, can quickly see how many windows of a given application there are, and can easily see when your selection has moved past the last window and back to the first. Basically, it works very well and should be taken as an example of the correct behaviour.
In compiz:
1. Only three window previews appear on screen at once, regardless of how many windows there are. This makes it impossible to see how many windows you have open, or how many windows of a given app, without cycling through them all and counting. And it means you don't easily know when you have cycled back to the first window, you have to recognise it when it comes around again.
2. The selection stays still, while the windows move. This makes it difficult to find the window you want with your eyes, because they are moving. It promotes a slow mode of use where you press tab, wait for the next window preview to focus, look at it and decide what it is, then either release alt or press tab again. (As opposed to just finding the window you want with your eyes becuase they are all on screen, then quickly pressing tab the right number of times to move the selection to it.)
In both aspects compiz should be changed to match metacity.
A further improvement, Alt-Tab has two use cases.
1. The user is searching for a window to switch to. In this case the window previews and window highlighting are useful.
2. The user knows which window is the previous one, and just wants to switch to that by pressing Alt+Tab once, for example when switching repeatedly between two windows by just pressing alt+tab quickly. In this case the window previews and highlights serve no purpose except to make the screen flash in a disturbing way, especially if either or both of the windows are maximised.
There should be a brief delay before drawing the window previews and highlights. If alt is still held after half a second, say, they will be drawn. This would allow very quick switching to the previous window without the screen flashing.
I have the same reaction, and same goals. When I have 20 windows up, it is a real pain to find the one I want. This was easy in metacity.