I did some work with this technique today with my wife, who is current LE. I was using a training gun, so we were safe. As you said, I found that I could protect my neck, head, and left eye MUCH better. One more tool for the toolbox.
I would like to see some techniques for defending from that position. I worked out a couple, like going into an arm-bar, and a palm strike to her face (NO, I didn't really hit her), but with limited mobility, I felt off balance. What did work, was crossing over with my right hand, after I holstered, and grabbing the back of her neck, and pulling her head down to a knee in the face. Something I thought might work, but didn't try it with her was to simply beat her in the face with my pistol...kind of a last resort thing.
Man, it is nice to beat my wife up every now and again...lol. Since the truth is, she is 6'2" and 185lbs, and is more than a match for most people I have ever met.
If you are ver in the AZ area, and have some techniques for mobility-limited people, I'd sure attend that class.