I'm glad to hear that.
About 6 or 7 years ago, I was driving a GMC Envoy. I had it in 2WD (driving the rear wheels) with cruise on. As I was coming down a steep hill on Hwy 9 outside of Orangeville, the vehicle downshifted (which it did sometimes to slow down and maintain the speed setpoint on downgrades) and due to black ice that I was unaware of, the vehicle spun out when the rear tires lost traction. I spun 360 degrees into the oncoming lanes (fortunately no cars coming) and when the vehicle hit dry pavement, I peeled two tires right off the rims and went backwards into the ditch. To this day, I am amazed it didn't roll (and am thankful there was no oncoming traffic). That car had traction control too. This is why I get concerned about aggressive re-gen on the rear wheels in slippery conditions. I know the Model S is no top-heavy SUV, but that experience has made me very sensitive to this issue.
I still don't understand why people are so aggressively against the idea of making an option to move re-gen to the brake pedal (activated when the brake light switch comes on) for those who want to coast when you take your foot off the accelerator and rely on the brake pedal for stopping. Those who like one pedal driving would leave it as is. I would likely leave it in standard mode all spring, summer and fall but would flip it over in the winter for these reasons.