One thing that I would love to have on mobile is an adaptive (?) video seeking. So you touch the "video cursor" and then move: the x axis is for seeking, but y axis is for sensitivity. Moving a finger along the bar (y = 0) is as things are currently - go to the right edge to seek till the end of the video. However moving it along the top edge of the video (y = 720) would only seek in terms of 5 seconds for example.

The scale between y=0 and y=720 wouldn't have to be linear.