I think it would've been a nice little thing to see, even if it were only for a few seconds. I missed the chocobos
However, where in the story would a chocobo appear? When you think about it, placing a chocobo in the film anywhere might just have seemed stupid. Ad SE do have a perfectly valid reason for not putting them in (the same as the large absense of Nanaki in the film)
That they wanted the movie to phail?
Red XIII > All the other characters (Bar Barret and Vincent)