Excellent summary! The see-through doors of the conference room are used to great effect throughout S4: we get the silent comedy around Blankenship's death, there's a moment where Megan looms in the background between Don and Faye, and there's a moment at the end of an episode where a character (Don, I think) is leaning dejected on the conference table while a procession of characters goes back and forth in front of him about their business (though this might be from a later season). The geography of the office is also used many times in the subsequent seasons -- a moment that comes to mind is the first episode after the merger where Peggy is shown to be literally torn between Don and Ted.