I'm conflicted on where Crocodile goes in the power chart :/
I know Luffy beat him way back when but Croc is still very powerful and they showed that well in the Marineford arc. Now I know we haven't seen him in the New World yet so maybe he also got stronger during those 2 years, but who knows.
help guise
Also power levels are a bit iffy, as it's possible for a Devil Fruit power to completely or partially nullify another's Devil Fruit power. For example, Enel would probably rock the shit out of everyone with his lightning powers, it's just too bad he fought against a rubberman eh? Also Buggy has a massive advantage over Mihawk (who could probably just punch Buggy to death when he finds his sword useless) although I don't know if a Haki-infused sword would still be effective.
Following that, it's easy for a low power fighter to beat a high power fighter if the matchup is in their favour. Also it seems like successful sneak attacks can massively damage even the strongest people.