Speculations I know what Luffy's dream is

[Impact]

The reason why people are shocked at Luffy for revealing his true dream is because it's based on the idea of paradise and imagination. It is something ONLY a child could believe in. Luffy is basically Charlie, the boy who Wonka wanted to inherit the company. If you must, you can compare Roger to Willy Wonka because he basically put out golden tickets when he announced the Great Pirate Era.

I'll tell you exactly what it is and you can make perfect reasoning with it just based on the narrative clues themselves.

1. Willy Wonka's Paradise of Pure Imagination

Pure Imagination:

Come with me and you'll be
In a world of pure imagination
Take a look and you'll see
Into your imagination

We'll begin with a spin
Traveling in the world of my creation
What we'll see will defy
Explanation

If you want to view paradise
Simply look around and view it
Anything you want to, do it
Want to change the world?
There's nothing to it

There is no life I know
To compare with pure imagination
Living there, you'll be free
If you truly wish to be

2. The Emperors of the Sea all have very big dreams usually based on changing the entire world including building their own paradise kingdoms.

Big Mom is the most obvious case with that kind of dream because she tried to make a Dream Country where all races existed. However, it had weird structural flaws like they all had to give her a portion of their life force on a regular basis. Luffy's dream is also like that except he wishes for a world where everybody can make their dreams reality. He calls it paradise.

 

[Punk Rotten]

Hmmm I can’t rule out the possibility, it’s a good one considering devil fruits are manifestations of dreams and desires. Goes with the theme of the story and grand enough to seem impossible and child like.

A good idea but I’m sure the nuance of how Luffy achieves the dream will be interesting and a bit subversive. Subverting the obvious is what Oda does best or exaggerates it.