I think no matter how strong the DF is finally it's up to the skill of the user who uses it, common example is Whitebeard and Blackbeard.
Whitebeard was quiet OP because he knew how to use his DF, although Blackbeard wasn't able to use whitebeard DF that much skillfully, but we need OP DF's, I am expecting Roger DF pretty much OP.
Whitebeard was quiet OP because he knew how to use his DF, although Blackbeard wasn't able to use whitebeard DF that much skillfully, but we need OP DF's, I am expecting Roger DF pretty much OP.