"And I think that you must never try to explain how he got the way he is or why he did what he did."
If a character does or says something that isn't justified in some way, then it's not organic or believable. So I think you do have to explain it - not by exposition - but by a prior event or action. However, Kubrick was a master filmmaker, so I'm sure I'm probably misinterpreting the quote.
I think this is a fair point on the value of exaggerated actions. The actress' reaction in 2:44 completely pulled me out of the immersion of the film, since she really over acted. If someone did that today the audience would laugh, not empathize. Even some of the other shots feel dated and over the top, to the point that I honestly could not imagine being successful today.
However, the analysis on movement was really useful and insightful and I will definitely try to keep that in mind for my next project. One challenge I can see is achieving the right balance, since it could dilute the potency of an actor's performance if the motion becomes distracting vs. enriching. Hence one of the reasons he is considered a master. ;)
Nice work Tony!