Ok so I joined a chocobo leveling party. There really is only 1 good spot in the whole game for leveling chocobos the to the east in quarrymill with the water elementals and bug looking guys.

We had 4 people war, blm blm whm and 4 chocobos. Grinded mobs for 1 hour. My chocobo is rank 7 and I got 80k exp and I need 700k to level. It was like I was playing old school FFXI with this leveling rate.

The TNL gets a lot higher at ranks 8 and 9.

I think you need to lower the amount of EXP chocobos need or buff the amount of exp monsters give chocobos. Currently its a very huge grind to level them and its not all that fun since your grinding the same mobs over and over again.