Oden didn't aim at defeating every swordsman and cutting everything.
From our perspective, Zoro isn't going to have more fight with Enma than the rest with their swords; from in-verse logic and the narrative behind, Zoro is indeed going to bond more deeply with it. Again, it can't be a coincidence that the only people who forged (or will forge) a black sword have a goal based on fighting their way to the top of swordsmanship.
I highly, highly, highly doubt Roger, Oden, Rayleigh, Shanks, whoever you think of who isn't Ryuma, Mihawk or Zoro ever cared about looking for the strongest to defeat them. Ryuma was looking for the "King" as per Monsters; Mihawk has been said to look for adversaries until he didn't find anyone left; and Zoro's whole dream is about achieving Mihawk's title.
I'm convinced this will be a defining factor in forging a black blade, potentially traced back to the "warrior's soul" that Monsters talked about. Ryuma, Mihawk and Zoro's goals is about being warriors. Anybody else, so far, had other goals that indirectly forced them to grow strong, but never directly aimed for warriorness itself.