For a lot of players there really isn't any in-battle benefit to leveling your chocobo. The new chocobo suit is definitely a step in the right direction (even though we're missing a mask to complete the set at the moment). However, I personally feel the attack/healing/tank power of our chocobo companions needs a buff. There seems to be no difference between having your chocobo summoned to battle or not. That said, I'd like to get to the main idea...

"Chocobo" Dungeons
In short, it would be a "solo" dungeon where you and your chocobo fight through the dungeon to obtain gear. (The gear can be chocobo-themed as well - Chocobo armor, accessories, weapons, etc.) It also opens the possibility of going into group dungeons with friends and their fighting fowls as well.

Additionally, I'd appreciate the ability to either reset your chocobo skill tree - or ability to master all chocobo skill trees implemented.