That's a valid concern. There are a lot of scenes that I think they only included to pay tribute to the comic, like the one in Rorschach's origin I mentioned above, when they coulda easily been replaced with something more functional to the plot. Dr. Manhattan's awareness of his future plays a very small role in the story of the film (the "I'm sorry, I'm informing Laurie 30 seconds ago" scene isn't there), but it's mentioned constantly, a lot more than in the comic. Again, I know what the point is, but I'm not sure if it'll come through to most of the audience.
I gotta say, though, nothing can prepare you for how cool Dr. Manhattan in Vietnam is.
