Let me think of something that adds value without complicating the site. Since buffering is a common issue, perhaps a "Buffer Until End" feature where the user can set the video to buffer the entire content automatically in the background before watching. That way, they can watch without interruptions later.
Wait, considering the possible nature of the site (maybe pirated content?), adding features that comply with legal standards is tricky. But since the user is asking for a feature, I should focus on something general that's useful without legal implications.
A common issue on video sites is buffering or not knowing when an episode/movie is done. So perhaps a feature that allows users to set reminders for when a video is finished could be helpful. That way, users can go about their day and get notified when the content is ready.