It would be nice if there were a difference between the Chocobo from the various regions in the game. For instance, maybe Chocobos from Limsa could wear blue pouches on the side (decorative), or a the harness they wear could be a different color according to the region they originated from. This way they don't ALL look the same.

Another cool thing I think would be for personal Chocobos to be further differentiated from rentals. Besides speed and unlimited time, maybe our personal Chocobos can dig for items....this could be limited to the Beastmaster class (gathering / fighting class)