The geometry of reach can affect where the head goes also. If you don't run much reach, the geometry of your arms raises your torso. And in consequence raises your head since it's connected to your neck which connects to your torso. More reach means that angle cuts that torso height. So, not only pad width. But he's right, too narrow and the head tends to pop up.
Just that lots of folks run lots of stack then worry about not being able to get the head down where if they lowered the stack some they don't need to stick their neck down like an ostrich.
I think with enough reach and the days of shorter cranks the hip angle thing isn't as big a deal.