I don't think getting your chocobo to rank 10 in a day is what they had in mind when this feature was added. I used my companion chocobo while farming over a couple days and got it to rank 4. I think that is pretty fast when you compare it to say FF11's chocobo digging where it took well over a year of daily digging to rank up the hidden chocobo stat.

I personally love using my chocobo companion. On my level 20something arcanist with Topaz Carby, we can kill things endlessly in droves. When farming, I can kill things faster and have some light healing backups.

While sure, there are some things that could be improved like allowing the chocobo to stay out while Duty finder is active, or being able to ride another mount while leaving the chocobo out. The major aspect of the chocobo companion I feel are fine.