I guess if we're going to start projecting expectations, what makes me most excited by what I see in the trailer is the clear breath of editing elements available to Malick's use.
From Badlands and Days of Heaven to The New World, he has been happy with his paint brush method of sweeping camera shots and elegant composition sight lines. Of course I short change his accomplishments by restricting my identification to those two peaks, but what he has accomplished in the 1970s was only marginally extended upon in his later films. Of course, the main addition in the Thin Red Line is the play on memory and how he wraps the structure around the organic idea of memory. His use is fine, but other filmmakers used first person camera angles and mixed it with distinct look back at earlier events. It's an old trick. The major addition is that Malick is utilizing his style to do it. Makes the film a little more provoking, but still, I felt more could have been done.
In the New World, at the end of the film, when Pocahontas dies, the film wraps up with a wonderful editing soliloquy on her life. An Indian appears in the back of an elegant English room and the film compartmentalizes a lot of different images together (from her life and surrounding) to be a final breath on her life. It was Malick's most inspired moments of filmmaking for me. I want a film that has that level of ambition throughout. With the way he's going to mix mystical elements of death and past, I feel Tree of Life may be ambitious enough for him to challenge the very core of his directing vision.
He's an exhilarating director in that every inch of his films draws me in to care on some level, but I have been a disenchanted viewer because I always wanted him to challenge the lines of his brush strokes more. The Thin Red Line has a focused development with creating memory. The New World has an inspired finale. I can see him ready to combine his effects for an entire film.