No One Piece villain, except maybe Doflamingo, has the aura of villains like Frieza, Cell, Super Buu, Pain, Itachi, Obito (pre-reveal), or Madara. I’d even argue that more minor villains like Sasori have more aura than many arc villains in OP tbh.
I think a large part of it is that OP villains usually don’t have as much of a backstory, so they end up feeling like generic baddies who are just there to be an obstacle for Luffy. I mean ffs, even Sasori, who only fought Sakura and Chiyo for a few chapters before being written out of the story, had a longer and better backstory than Kaido…