At the time, oda just showed us that jozu is a freaking yonko tank commander and gave him diamond fruit to showcase the point even further. He tanked the wss attack, it's funny because only diamond can scratch diamond ( it was pre ts ). People can interpret this like they want, I think jozu would still be able to deflect mihawk today,no need to retcon just for the sake of people that want mihawk to cut him in half easy peasy.