I haven't seen the trailer but here's what I think.
There are two things about this game which will be no secret to even the most casual of gamers. The first is that Aerith dies. The second is that Sephiroth - not Shinra, not Rufus, not Jenova, but Sephiroth - is the real villain, and not just any villain, but one of the most iconic villains in gaming history. There is just no way they could replicate the mystery and the build-up that the original game provided. In the OG, when it came out, we didn't know any more about what was going on in the plot than the characters did. Now we do. We simply know too much. It would be like making a movie about Hitler and trying to persuade the audience that he's a warm-hearted vegetarian who loves children and dogs, and then suddenly - surprise! - mass murder.
So IMHO Square Enix have accepted this fact about their villain and decided to roll with it. They haven't just re-made this game for new players who refuse to play the OG because its graphics are too old. They have remade this game for its fans.