I don't know if playing video in reverse it yet even possible (I can't get the Trickplay Reverse icon to display, so I only assume that's what it does), but if so, I would love to see an option for using the MouseWheel "hotkey" to do one of the following:
1) A feature similar to your DVD player. While the DVD is playing, you can press Fast Forward or Rewind and the picture continues to play. The scroll wheel represents those buttons where for every tick forward the video increases speed by 10% while the video continues to play in a forward direction; a single tick in the opposite direction (backwards) is like pressing Play, stopping the FF no matter how fast it's going and returning the video to normal speed. In the same way, for every tick backwards the video increases speed by 10% while the video continues to play in a reverse direction; a single tick in the opposite direction (forwards) stopping the Rewind no matter how fast it's going and returning the video to normal speed moving forward again.
2) If the first is not possible, just the ability to use the wheel to speed up and slow down a video.