I think I suggested this a long time ago, pre-HTML5, and perhaps it’s a good time to look at it now.
When replaying a hand, it would be great to have some “VCR Controls” that we can use to play, pause, step back/forward the events of the hand. I think this would be very useful for reviewing the hand in, say, a video where an instructor gives remarks at various points in the hand.
The way the current playback system works, it just runs the hand in realtime without any controls to allow the viewer to pause, etc., so if you wanted to talk over the hand and give commentary, you don’t really have adequate time to do that, and the hand will just proceed along as it did when it was originally played. This limits the usefulness of the replay option.