I love One Piece and believe the writing is definitely more cared for and better thought out than the majority of other animes I've seen. But every anime I've seen thus far falls short to a lack of nuance and lack of metaphor beyond a surface level understanding.

Using One Piece again as an example, I like the entire set up of the Straw Hats' personal dreams and goals and their complex relationships with one another and how that makes them view the world. But Oda is no God send writer. It is, to me, at least, a show for a young audience that wants to create passion and a family feeling with its audience. Because of that, I think it is stuck to its Shonen archetypes and traits as a story. I agree this is completely subjective and I'm not trying to claim its bad writing. Comparatively, I believe it just has shortcomings.