Folks want more. They want their trains to do more to increase the play value. Lionel innovated to add to the play value.
IMO as cool as the coal load is, I really wish they would start making accessories and cars that take advantage of Legacy. Enhance operating cars and track side items to work with the trains.
IMO though, I think we'll see a coaling setup to go with the Big Boy that will enhance the coal load feature. Don't quote me but I have a funny feeling that the coal load is just the beginning.