You guys are missing something very important
Law's DF even though it's Ultimate DF & Hax cannot work on someone with Very Powerful Haki
Imagine Shanks!
I will say it right now, Shanks Powerful CoC makes DFs useless against him
Roger too & that's why he can Equally fight WB who had a Powerful DF on top of Haki & Staff & Strength
The Ability to Conquer even Devils inside DFs!