Comment by Per_Bothner

On Gnome, the Super (Windows) key does an Expose (show windows reduced-size and non-overlapping) and lets you launch applications (and more). On KDE 5, the Super key brings up the Application Launcher, which is nice. And Super+W (which isn't too painful to type) does an Expose. But it would be nice if there was an option for Super to do an Expose and bring up Application Launcher.