Okay, first off Sabo was the strongest person in Dressrosa. And I'm willing to debate it. He was casually handling Issho/Fujitora, who's an ADMIRAL, and about 50 other Marine fodder at once, and complaining that he wasn't a big enough challenge. He was able to casually destroy the Coliseum a second after getting the Flare-Flare Fruit, and he stomped Burgess in the tournament. His Haki is top notch, he was using nearly all of Ace's moves right after getting the fruit, and one-upping him by imbuing his staff with flames. Let's not forget to mention he's Number 2 in the Revolutionary Army, right behind Dragon, who's the most wanted man in the world. He has a higher rank than Kuma before he got turned into a Pacifista, and he's stronger than Ivankov.