Well swiping down in the application menu would be scrolling it wouldn't it? But I do agree swiping up on the desktop could bring you to the application menu or switcher. Though what do you do once your inside an application?

Though it would be useful to have a widget that could go on the bottom left to activate the switcher (well I'm sure it can probably be coded)

What is the two clicks way?

Also, isn't there also the related situation that, to switch between two fullscreen apps, you have to go through the task switch button and have three clicks? One to hit button/overlay on lower right of current fullscreen app, two to click on task switch button, and three to click on desired app. (In Diablo, you could toggle to the next fullscreen app directly using the home key without any intermediate screen).