I still think there were plans of a resurrection, that got cut, either because of time, or purposely cut for a dramatic effect. Maybe both....were true. Maybe because of time restraints, an alternate ending was dropped. You know....Shadow Hearts....awe never mind, I don't want to spoil it.
There are too many little things, that point to a resurrection....such as Red13's Grandpa's speech. (can you tell...I can't pronounce it, thus can't spell it), the mirrors that don't do anything in that ancient city.... The Materia Natural fountain, in Nibiliem (sp). Tifa saying that it wasn't Aeris' intention of dying. The infamous picture of Aeris looking at the Highwind. And why did Marline say "the flower girl?", during the ending movie. Just little things that seem, out of place. There is even pieces of dialog for Aeris, if you do that hack, of getting her back into the party, that were left in the game.