How is Doflamingo weaker than Jozu/Vista?
Law's haki has been shown to be strong enough to block a tough portion of Doflamingo's string. Considering the parasite move is made of a slimmer version of his string, it's safe to assume, it can't bypass strong enough haki, if haki at all and considering it aims for the neck to control the target, as long as a haki user cover his neck, the parasite is useless in a fight. In Jozu's case it's even worse considering he can cover any part of his body in diamond, so it also has to bypass the durability of the diamond product, even before bypassing his haki, even before trying to control him with the move, in other words, completely useless to him in a fight
His haki isn't that great either since he has been shown to bleed from the cutting edge of a sword
Furthermore, Law's swordsmanship has been shown to be great enough to block Doffy in close quarter combat. There is no doubt that Vista should be a much greater swordsman than Law judging by his little skirmich with Mihawk and his hype of being WB's strongest swordsman, so even in close combat, he should manhandle Doflamingo. Considering Jozu should be stronger it's even worse. Doflamingo's physical strength is also not great enough. A hakified punch barely left some bruises to Luffy's face despite it being a direct hit. Similarly, a high tier punch made him cough up blood. Jozu's physical strength and speed will end up being too much for him
He can maybe use the black knight to avoid close quarter combat for a while, but in the end he can't do much against either of them. As long as Doffy's hax is neutralized, he isn't that strong compared to them
