I would love it if it would at very least blank the screen after a period of no video activity.
Maybe dim after 5 minutes, blank after 10, or maybe user configurable steps.
Actual screensavers would be nice, but dimming/blanking would suffice for me.
Music visualizations would be nice too, but not as easy as screen savers, and no where near as easy as dimming/blanking, so way lower on my nice to have list than the other options…