Pitch
After a few seconds of video-playback in full-screen-view, hide the controls of the video-player, and, if there is one, the mouse-cursor. Show those again, after tapping on a touchscreen, moving the mouse-cursor, or pressing a keyboard-key.
Motivation
Currently, the bottom of videos is covered by the player-controls in full-screen-view, and a mouse-cursor can also be visible in front of the video (sometimes also showing alt-text next to it). With this feature, one could see the entire video, with less distractions.