Hmmmm…...
Just an idea.
So uh, what exactly was the point of Coby explaining the crossing? Tie up a loose end? Okay. Cool. Didn't really ask for it but that was nice of Oda....but why did Nami have to hear that?????
Think there's a possibility for some adventures outside the GL?
(it has indeed occurred to me that this may have been brought up before so I apologize if this idea was already beaten to death)
Isn't the whole point of the sea beyond the Gates of Justice that there are large sea kings there (like those found in the calm belts), and the Marine HQ ships have a way to navigate those seas? It's possible that there are more of these giant sea king nests in the GL, and at some point the SHs might have to navigate them.