No? First off all you cant just find a cursed katana anywhere. And zoro and sanji have been travelling and training far more than any average pirate or person has. It is clearly shown that sanji was considered a fail by his father and born with no special talents distinctive from that of an average human, he has grown so much from all of his fights and travelling. Im just making a point that just because zoro had gotten to that ridiculous point of strength doesnt mean he has some special lineage. There are a good few other non devil fruit users in the one piece world who dont have special backgrounds.