I would like to request a "Walk through Activities" shortcut, analogous to the existing "Walk through Desktops" and "Walk through Windows" shortcuts.  The difference with the existing "Next activity" and "Previous activity" would be that you don't cycle through all Activities in a fixed order before you get back to the current one, but when the shortcut is used twice (with a break) you go back to the previous activity (i.e. you keep track of the history).  The same difference exists between "Switch to next Desktop" and "Walk through Desktops" in kwin.