fastjet2k, the point you make about a/c height differential with the steps as pax get on and off is a good one. Unfortunately I cannot see a ready fix for this as the steps do not have a means of automatically shadowing the fuselage in it's rise and falls. When the a/c comes onto stand it will be heavier, and it is necessary to fit the steps safely under the door and level with , or just a smidgeon below, the floor height. They cannot be higher because on most aircraft this would prevent the door being opened! Likewise for boarding they cannot be raised to door level because the fuselage will drop as the aircraft fills up, and if the steps were up higher they would snag the door again.
I guess it is something which pax have to made verbally aware of.