I hadn't seen the film in years, but I watched it the other day and realized two things: first, that my belief that Robert Altman is insanely overrated as a filmmaker was 100% correct; and second, it's a really uncomfortable movie to watch.
For one thing, it's not that funny. I laughed at the football game, and I laughed at parts of the trip to Japan, but most of the wisecracks aren't that good, and the main characters, with whom we're supposed to ride along, are incredibly unsympathetic and nasty. I wound up feeling horrible for poor Frank Burns and Hot Lips Houlihan, who suffer terrible indignities for no real reason at all.
Sally Kellerman got so annoying and insufferable in later years that it's easy to overlook how good her performance in that movie was. On the page, her first scene with Hawkeye comes off with Houlihan being perfectly reasonable and Hawkeye being a sleazy, browbeating fool; the only reason you sympathize with Hawkeye even a little bit is Kellerman's splendid holier-than-thou reading; it fools you into disliking her character when there's absolutely no reason you should. Robert Duval doesn't sell Burns's unsympathetic side as well, and so I can't help but feel bad for him when Hawkeye starts making crude fun of him ten seconds after they meet just because Burns takes a little too long to pray. Later, Hawkeye complains that Burns is a poor surgeon, but we don't see anything to that regard; he is short with an untrained orderly who takes too long to bring the right tool after a critically injured soldier dies as a result, but that's not an utterly inconceivable reaction, and Houlihan, whom Hawkeye grudgingly admits is a good nurse, thinks Burns is excellent. The effect is that Hawkeye and Trapper set about making Burns's life hell without the audience coming to think that Burns deserves it; the movie makes you take Hawkeye's smug assumptions as gospel. But think about it: Burns's form of cultural imperialism is to use the Bible to teach a laundry boy to read; Hawkeye's is to get the kid to make him martinis. Who's the Ugly American here?
The movie doesn't have an arc, by design; it feels odd and disjointed, and you're dropped in and out of it much like Hawkeye is dropped in and out of the war. That's reflective of the setting, but it's in keeping with Altman's stiff filmmaking. Y'know who Altman reminds me of? Serious film buffs will consider this heresy: Blake Edwards. They've got talent, and they can make things happen, but they're really stodgy storytellers who confuse harassment with wit and self-indulgence with charm. Altman is An Important Filmmaker; Edwards just tries to amuse himself and make entertaining flicks along the way. But I know whose movies I'd rather see.)