Originally Posted by
Big D
The people responsible for the story would disagree with you there... according to them, the wolf is a symbol of Cloud's guilt. His self-blame over Aerith's death, and all the other nastiness that he blames himself for. That's why it appears at key locations: the Buster Sword, the church, the Forgotten City - before disappearing when Cloud's finally made peace with himself.
I don't have a link, but I'm sure Kishi or somebody will post one before too long. But this interpretation was confirmed by one or more of the senior staff of AC.