I don't buy it, the type of drive makes no difference in the stopping ability of the car. Sure, all season vs. winter will make a difference, but AWD vs FWD? Shouldn't. You agree with this fact, but your data shows otherwise, I don't get it...
As for winter tires, sure I agree that if you live somewhere that gets a lot of snow, then yeah winter tires are worth it. But if you get snow even just on a monthly basis, in all honesty all season are better. You talk about the minuses of all season tires in the snow, but what about the minuses of winter tires in the wet or the dry? Dry traction is radically reduced with winter tires (this is getting less so) and rolling resistance is dramatically increased. If you have no snow more days than snow, then I reccomend you stick with all seasons.