Days of Heaven: A potentially beautiful film gone to waste

Let's start with the positive: Terrence Mallick's 1978 film "Days of Heaven" is absolutely beautiful to watch, and the Criterion blu-ray version on a big screen is just great - one astonishing landcape shot on the Texas prairie after another, and each shot composed with a delicacy and sense of balance, line, and color - you couldbe watching "The Gleaners" come alive in cinematography - and then there are the close-ups, the faces like Evans photos, stolid and full of character, even the locusts consuming the wheat, and the fires at night on the plains like Whistler, dark and mysterious - so I'd say get the DVD and then - turn the sound off and just watch it, because the story is preposterous, poorly constructed, dragged down by a stolid script, clumsy acting, poor casting, and a melodramatic score. Anything else? Well, the narrative voice, meant to be a teenage girl?, never clear from what vantage she is telling the story, sometimes seems like a kid, but her vocabulary and sentence construction sounds like: a screenwriter. Richard Gere and whoever plays his wife/lover/sister - who knows what she is? - are OK, but the young Sam Shepard as a lonely, wealthy rancher is absurd - way to handsome and cool for this part, meant to be lonely and bit of a loser. Most of all, we never have any idea why Gere and (unnamed) girlfriend/wife pretend to be brother-sister, it's never clear whether they are scam artists trying to capture Shepard's fortune or if they're unfortunate lovers. As a result, we don't understand them or their motives, don't care at all about them when they're in flight after Gere kills Shepard (his 2nd killing - is he a sociopath, or a victim of a bad screenplay?). And lest we forget this is the swinging 70s, for no reason at all two airplanes suddenly land on the prairie, replete with an Italian flying circus (what hath Fellini wrought?). Mallick (sp?) apparently does not develop traditional narratives and works on the level of symbol or allegory - but whatever he's after her totally eludes me. Clarity of narrative would help. A potentially beautiful film gone to waste.