I like to see lectures like reading, with regressions and tempo variation. This is done by hotkeys, which are especially important in full screen mode, which is also advisable because even fewer controls are available in this mode. But, unfortunately, player has no reaction on hitting the button despite the information bar saying explicitly which are supported (you should be able to show/hide it with H key).
Right click on the video and select "Show Controls".
Then you can go backwards and forwards by 15 s with the arrow keys.
If by hotkeys you talk about keyboard shortcuts. I have found something for Firefox in Coursera.
By default, the shortcuts work on Youtube but not on Coursera. However, if you click right on the video and select "show the controls", then the shortcuts work.
Note: sometimes it stops working and I have to hide again then show again the controls.
This is incredibly frustrating but can be cured. Switch player type (to Flash or backwards to HTML5) and shortcuts are activated.
Actually there is an Firefox extension for this: Add Hotkeys to Coursera. You will also get more precise controls on playback speed, seek, volume.