Don't have time for a long post on this subject, but I was watching Grand Illusion again yesterday, and I noticed that while Jean Renoir pulls off some great technical feats in this movie, he doesn't always save his big camera flourishes for the biggest scenes. Many of the "big" scenes -- the escape, the death of Boildieu -- are shot fairly simply; they're not technically weak, but the camera setups seem pretty traditional. But when the characters first gather for a meal in the POW camp, the camera goes wild, circling around the table, constantly in motion. Renoir called attention to the unique way he shot and edited this simple dinner scene. There are some big camera swoops in the "La Marseillaise" scene which Michael Curtiz, when he did virtually the same scene in Casablanca, staged in a more conventional way.
It's interesting because today, I think there's a default assumption that the biggest technical challenges should be saved for the biggest scenes, and that small-scale scenes, like meals or simple conversations, are shot more simply and economically. But first, doesn't it make more sense to try something technically unusual to liven up what could otherwise be a static scene, instead of saving them for the scenes that are inherently exciting? And second, since unusual techniques are expensive and time-consuming to get right, doesn't it make more sense to try them out in a scene that doesn't cost a lot to shoot in the first place, and shoot some of the more expensive scenes in a more "classical" manner?