My long opinion on this, sorry. I think koby is okay as a coc user, however, I dont like the idea for koby to have advanced conquerors haki only because i dont like the idea of koby getting this strong without oda ever having shown us any serious fight or situation koby has been in repeatedly to put him on the level of a strong haki user, let alone acoc user like luffy and zoro. Thats what oda said through rayleigh is the way to get stronger truly, extreme battle. We havent seen koby in any 1 v 1 seriously near death many times to get strong, only training on the battleship bags thing which is lame. Training like that as a marine, even if its more than normal, can not be enough at all. It feels like a forced power up instead of being natural through fighting the most powerful. With that being said, law doesnt have some dream of being powerful with a title to show it. He has to be powerful, and he is, but he doesnt dream to be powerful and competitve in and of itself by nature. Law is more sit and wait, or oberseve and calculate, he can be competitive and reckless and show great will, but its not by consistent nature, only when absolute need be. King doesnt have any aspiration to be strong through a title in and of himself, he just wants to be under kaidos wing as a powerful agent for him since they met. similar to ace for whitebeard, but ace tried to kill whitebeard many times and developed emotional connection to him over time why he wanted to make whitebeard pirate king. Ace had his own dreams before whitebeard, king never had that. King was always just kaidos henchman. He has no qualities of his own to stand above others with a title by his own separate dream or others thoughts of him. Koby always wanted to be a pinnacle example of justice, as a marine admiral, thats a powerful title, that alone says alot. Kobys personality is humble, kind, shy, non assertive, empathetic, sacrificial, and has alot of humility. He is the ideal personality of a hero. What i realize is coc users dont all have to have the same headstrong, reckless, competitve, overly confident personalities with insanely traumatic history, and to have always been strong bc of them and openly desiring to be strong and competitive with no regard for their well being, like luffy, zoro, kid etc. , it seems to be a base line consistency among coc users ro he overtly confident and cmpetitive and headstrong, However, koby does drive to be strong, and wants to catch up to luffy and zoro, and is reckless like them, has a big dream like them, just not overtly by personality, he drives to be stronger and push himself in secret, but still drives to be strong just like them, he doesnt have their open confidence to know their strength and openly show it and say their dreams proudly and want to compete with others by them. Koby has the qualities, but hes just not like them in personality, and thats okay.