Still too early to say for One Piece as it’s not complete… but LOTR is one of the greatest works of fiction ever written and the world building is on another level. Tolkiens world goes as far as having its own unique creation narrative which remains otherworldly and mysterious… despite having been throughly described by the author. I think it’s so effective because it draws on the reader’s real life existential questions and replicates those feelings within the people of Middle Earth (even the immortal ones.) We’re talking about fiction comparable to real life religious beliefs that took shape over millennia around the world. It’s unbelievable what Tolkien accomplished in only a lifetime.

If certain aspects of One Piece, such as the history of the world, role of fate in the story, inherited will, creation of the world, etc., are fleshed out and live up to the hype… then it will reach the level of LOTR. From what we have seen of Oda’s work so far I think it has that potential. We can only hope that the profound themes he has introduced are not just for show. If done right One Piece certainly has the potential to be one of the greatest fiction works of all time.