Several times a year I dream that a new version of Advent Children is released, usually including some new fights against the silver-haired-trio and/or an extended Cloud vs Sephiroth fight. I can't recall if any improvements are ever made to the story and/or pacing of the movie.
I'm going to interpret this as a sub-conscious desire to be delivered something new from this title, in a similar vein to how I find new enjoyment in Crisis Core and Dirge of Cerberus by hacking these games. The problem with a movie is that I can't hack it.