The selection of the Shichibukai was actually a complicated process. Not only did they need formidable strength and a certain degree of intimidation, but they also needed the World Government's approval.
Strength alone was useless. Defeating a Shichibukai did not mean one could replace a Shichibukai. If the World Government was dissatisfied, defeating one Shichibukai would only bring even harsher suppression.
Although the Navy had the authority to nominate Shichibukai, the World Government still had the final say.
The Navy's candidates had to heed the World Government's opinions, but when the World Government made a decision, it had no need to consider the Navy's feelings.
"It's too early. A brat like him doesn't have the strength to intimidate the seas. We'll talk again after he achieves something new."
Before the Great Pirate Era began, Hawk Eyes had already started to make a name for himself, but his prestige was still insufficient.
At this time, Hawk Eyes did not yet bear the title of the world's greatest swordsman. Coupled with his different way of doing things, he could not meet the World Government's expectations for a Shichibukai.
"Speaking of which, Crocodile failed when he challenged Whitebeard. I heard he even lost an arm."
"That was Whitebeard. His defeat was to be expected. It was impressive enough that he escaped alive. Siderial is much more reassuring. If all the Kings of the seas were like him, we'd save ourselves quite a bit of trouble."
The selection of the Shichibukai still had to be handled carefully. It was acceptable for someone like Crocodile to lose to Whitebeard.
Whitebeard was simply too strong—so strong that no one thought losing to him meant one was weak.
But if a Shichibukai were casually defeated by some passing rookie, the World Government would have nowhere to hide