>>45857189I mean XY has a cool backstory, but that doesn't mean the world building is good.
In Sun and Moon you finish the game having learned pretty much everything about the culture of each island, their traditions, their worldview, their deities. All the characters are fleshed out to the point you can tell what their daily lives are like beyond the confines of the game and it doesn't just feel like everyone and everything revolves around the player and their journey.
The AZ stuff in XY is really cool, but beyond that Kalos is pretty soulless.