I'd love to see a new desktop icon/folder feature. Adding a specific type of New Folder that will only be displayed on your main/primary display desktop. The folder would always be visible on the main display and contain the icons that show up on all external monitors that are not flagged as the main display.
That way, when a laptop isn't connected to an external monitor, those sets of icons are quickly accessible via the special desktop folder on your main display. You would no longer have a flood of icons when using only the laptop and when docked you have them at their normal positions.