The previous shichibukai are a lot stronger than the post ones.
Only Mihawk will serve as a real threat to a yonkou one on one
Kuma will come in second of course, he a mass destruction that served under dragon.
They needed him
People like doflamingo and Crocodile can survive against a yonkou
Crocodile mentioned countless times that he fought Whitbeard.
Jinbei, Boa Hankcock, and Moria would get steam rolled by a yonkou giving them little chance of survival.
Moria used to be physically stronger but, kaido surpassed him and raped him when they got to the new world
Only Mihawk will serve as a real threat to a yonkou one on one
Kuma will come in second of course, he a mass destruction that served under dragon.
They needed him
People like doflamingo and Crocodile can survive against a yonkou
Crocodile mentioned countless times that he fought Whitbeard.
Jinbei, Boa Hankcock, and Moria would get steam rolled by a yonkou giving them little chance of survival.
Moria used to be physically stronger but, kaido surpassed him and raped him when they got to the new world