The narrative work in Sable was really underrated. The side stories are playful but always grounded in the world and it has such a consistently gentle and humane tone. I think that's so interesting for a big adventure type game in a fantasy setting!
It was such a smart move to make it a coming of age story about a character trying to find their place in the world because it dovetails so well with an open world structure and provides a hook for getting the player to engage and be curious.
To expand on that a little, I wish we had more games that put you in an immersive setting where the goal was to explore and learn about it, rather than master it. Games in this space tend to have a kind of pioneer mentality or else hang a lot on big, hard to relate to genre tropes like unlocking your hidden powers, building up to facing a big evil thing, prophecies. etc. It's refreshing to have something with fun worldbuilding and a wide horizon feeling that's also focused on something like: 'what's it like to live here.'
The narrative designer, Meghna Jayanth, has an excellent essay up called White Protagonism and Imperial Pleasures that touches on a lot of issues with contemporary games, and while she doesn't talk about Sable that much (it appears in all of one paragraph), you can see how the game fits into and pushes against the ideas presented in the essay.
Plus you should just play Sable. It's such a warm game, and its structure means that you get to travel the world, meet interesting people, and decide if you want to join them. The approach works like gangbusters, because as @mousefountain says above, it "encourages you to engage and be curious", not just on a gameplay level but at a critical one too.
"Am I enjoying this enough that I would I define Sable/myself by it?" is a powerful question, and really makes the game worth experiencing.