I like Chocobo leveling as it isIts nice having a variety of short, medium, and long term goals in the game. Chocobo leveling is one of only a handful of long term goals available atm and I'd hate to see that taken away. My chocobo is rank 6 now, half way to rank 7!
With the way Chocobos are designed rank 10 is at best handy to have while fating and that's about it. So no one is being gimped by not having their Chocobo at a high rank, so its almost purely about prestige, which means there's nothing wrong with only 0.1% of players having a rank ten Chocobo.