I think it would be nice to have video playback speed control. It would be nice to slow it down to 0.5 speed when you want to better observe certain video sections. Also, if you have the ability to replay sections of a video. Perhaps you can do it where you can select the beginning and end of a playback loop. If you had to choose just one of these features. The ability to slow down the video to 0.5 is the better choice.