I really do think they should stick with just Chocobo's.

However, not just the yellow variety. Different colors that can be breeded would be great!

If possible, it would be nice to see a chocobo that mirrors the job playing it.
Example: White Mage rider makes chocobo wear a pope hat and a white/red harness.

It would be one mount, with lots of customization options. Something that hasn't really been seen yet in online games.