The definition of a conqueror changed a long, long time ago. It used to be those who... y'kno, wished to be a conqueror/king of some sorts, or had king titles, or were in great positions of power etc...
Now it's just a sign that you have top-tier potential. I fully expect every major player moving forward to have CoC. Wouldn't be surprised if it's revealed the admirals all have CoC too.
Sabo essentially confirmed to be a conqueror as well, being a key player in the final arc. Coby's obvious.
The only way I have a problem with all of this is if Sanji's a conqueror and Law isn't, as Law has most definitely far demonstrated the qualities of a king much better than Sanji since even a child — at no point has Sanji ever been portrayed as Law's peer in any sense. That's the only way this is an asspull and makes no sense. Otherwise, we good.