If I were sitting in a car, I would would know that 4-D is basically shifting between fourth and overdrive. And if someone accidentally did shift from overdrive down to fourth, it won't kill the car in most circumstances. It's better than the old O/D button that asks your thumb to press it.
Ultimately, my proposal that this shift pattern groups gears by use-cases still holds true. D-4, 4-3, 2-L. If a person can't understand that, it's perfectly fine to leave it in D.