The twin suns scene is so iconic because it's so melancholic. Luke wants to join the Rebellion but he can't. Well, he can't even go to Tosche station! He wants so much and yet he feels trapped in this planet, without perspectives, maybe fearing he'll never fulfill his dreams.

I think we've all been there at least once in our lives, and that's why so many of us identify with Luke, feeling trapped, wanting so much and yet not knowing how to get there. The suns are far away, like his dreams. Like so many young people's dreams...

The twin suns in TLJ work. It's no longer in Tatooine. He's looking at the suns from a different perspective now, older, having achieved many of his dreams. There's no fear, no trapping, he's ready to let go. In a way, he's leaving the trapping of the physical world.

Now... WTF does this scene mean?

Luke's Tatooine scene in ANH is sad. It's not happy, glorious, or optimistic. If anything, it was about the fear of being trapped forever on a desolate planet, away from his dreams.

How can a young person's journey END there?

You can say, ok, she'll have more adventures. Still, symbolically, this is where Luke was feeling trapped, frustrated, and maybe even hopeless.

Rey can take the name Skywalker, but Tatooine's twin suns have no meaning in her journey.

Worse than a meaningless nostalgia shot, it's about putting a young person in the exact same place from where another young character wanted to escape. Where a young character saw hope as distant and felt sad and frustrated.

And our young hero here is frustrated. It's horrible.