Re: New Advent Children Complete trailer.
Most of the movie's problems can probably be attributed to the fact that it's got about 20 minutes worth of core story, and the rest is just fanservice fluff that was continually added on as the production continued until they finally hit a deadline and had to wrap it up. There was one script rewrite when they got the go to make a full-length film, but a lot of the movie just got made up as they went along.
Almost the entire speech Rufus gives during the Bahamut SHIN battle is superfluous, restating stuff that Marlene addressed in the first few minutes of the movie. One or the other was pretty obviously an artifact of an older version of the film and they didn't want to cut it out.
Now they've had time to sort through things and rework the weaker parts of the film, clarify details, add more exposition, and so on. At the least, it'll be better than it was before.
There are a lot of questions left unanswered; like, in my own case, why do we even need the SHM? And then, followed by my complaint of, it seems like a waste of three perfectly good characters. *shrug* ... Unless they are still separate from Sephiroth... ?!?
The Remnants, simply put,
aren't real characters. They're just physical manifestations of Sephiroth's spirit and, by extension, represent aspects of his personality (cruelty, allure, and strength).
Within the context of the story, they are nothing more than puppets, like Jenova and the Sephiroth Copies in the original game. They're golems, simple physical constructs that Sephiroth can control, driven almost purely by their instinct to find Jenova and carry out the Reunion.
I suppose it's possible that they can be recreated, but in terms of storytelling, I'm fairly certain that they've already served their purpose and probably won't be brought back into future stories.