Well, it depends on your goals. All the physical exigencies of the SG experiment require a great deal more theoretical machinery to describe and I think all the

Well, it depends on your goals. All the physical exigencies of the SG experiment require a great deal more theoretical machinery to describe and I think all the mix-states/pure-states stuff can prolong the period during which the student clings to the fantasy that some simple classical physical system is simply obscured by its size and the physical limitations of classical measurement. I do think a full accounting of the SG experiment is useful for the student, but if the intent is to describe the machinery of quantum mechanics per se, then details obscure, rather than clarify.