P.S. Long ass read, read at your own peril.. lol.
I think some things have already been answered already. At least, can call it my headcanon.
The way I see it, we know Luffy is Joyboy, Oden said he wanted to open the borders of Wano before Joyboy returned thinking Joyboy wouldn't be able to arrive if the borders of Wano weren't open first. A closed border means no one can come in, and it means they wouldn't allow people in - until Kaido was defeated, people coming in were viewed as threats.
The Kozuki were originally the only people who understood the Ancient Language since they were the ones who wrote and created Poneglyphs, and every firstborn Kozuki was endowed with the knowledge to read/write in the Ancient Language, it was Oden's perceived role to meet with Joyboy and help him interpret understand the full history and take whatever the correct course of action would be.
Of course, Oden died, but his death served a purpose narratively which was to allow Luffy (new Joyboy) to come to Wano, defeat Kaido and be viewed as a hero - in a sense, this opened the hearts of Wano to outsiders and stopped them from believing all outsiders are threats. A huge part of Luffy's destiny (
ugly term, but it is what it is) is to be viewed as a hero narratively which is why where he goes, Oda gives Luffy a villain to defeat and appear to be a hero, otherwise the world cannot trust him. This is why in places like Skypiea and Fishman Island where Roger visited, Roger did nothing to mediate in any social or political issues they were suffering from, but it paved the way for Luffy to come in, defeat the villain and become a hero.
This is why I still believe he was able to earn the trust of Fishman Island, Alabasta, Zou... I think WCI will also come to trust Luffy once Big Mom is defeated probably in Elbaph if I had to guess - why this is important to me is narratively, WCI is just too big of a territory to not become one of Luffy's allies because... the end goal in earning the trust of all these counties is to have enough forces to take on the WG (Gorose) as the end game.
As fate would have it, Oden dying doesn't mean Poneglyphs can't be understood because the knowledge isn't lost since Momonosuke never gained this reading ability for Ancient Language, Robin was born and learnt to read the Poneglyph.
Luffy defeats Kaido, and becomes Joyboy, yet Momonosuke doesn't open Wano's borders yet, why? Aramaki (Greenbull) explains why, without Kaido there to protect them from threats, they're vulnerable which is why Momonosuke understood the Samurai + Himself need to be able to fight off Admirals and keep the borders closed up until then - the Gorosei actually commended him for his intelligence, so we can assume they're training.
Wano's current geography makes them an impenetrable fortified fortress, ships can't get in easily, they'll get decimated with ease and can't be broken through easily, so the WG will not mount an attack anytime soon imo.
Once Wano's borders are open, they will be easily attacked because they'll be on regular sea level. The borders won't be open until 2 requirements are met imo:
- They become strong enough or confident enough to fight off enemies which will probably be in a year or 2 from now.
- AND the need for Pluton is required - we know the purpose of Pluton as stated in Water7 is to fight off any Ancient Weapons which adds credence to the idea that the WG do possess Uranus, but this is not yet common knowledge.
Fishman Island to me parallels with Cocoyashi Village.
Luffy defeated Arlong which saved Cocoyashi village and he destroyed Arlong Park (the room inside it specifically) because to Luffy, it represented Nami's suffering and symbol of slavery.
Fishman Island is the parallel to this imo, but from a Fishman to Human relationship. Fishman Island is symbolic of Humans (WG's) racism and oppression, and sometimes for Luffy, destroying things that symbolise pain is his way of helping people free themselves from their trauma, I think he destroys Fishman Island for that reason - Madame Shirley's vision looks evil, but not all destruction is evil, it can have good reason behind it.
Another thing is we know the Noah is supposed to be moved by the Sea Kings controlled by Poseidon. It is heavily suggested in chapter 621 that Noah's purpose is to help move the Fishmen to the surface.
Fishmen have always wanted to live on the surface and see the sun which is why the Fishman Pirates were called Sun Pirates, the Sun is symbolic with Freedom which ties in with Sun God Nika, the liberator.
Wills are things that people inherit. Whether it's from inspirational stories or having desires. I think D. just refers to the name of the Ancient Kingdom who had a philosophy completely opposite to that of the WG's which is slavery. Always thought the Will of D. just meant the will to bring freedom all over the world.
This is probably why we see that Shandians, Fishmen, Lunarians, Bucaneers are all related to Joyboy or the idea of Nika saving them. They're all seeking freedom, and Joyboy's goal was to help them live harmoniously, but the WG do not want that. They want to enslave everyone.
And I think Nefeltari Lily was a friend of Joyboy, well she's a D. so that makes sense to me. Imu says she's responsible for the Poneglyph being spread around the world, It's quite fitting that Vivi is now secretly a SH, or rather, has always been, so would be nice to see how they come together.
One thing I'll always believe is the One Piece is just the 9 Poneglyphs (Real Poneglyphs/Rio Poneglyphs) that detail the truth.
In retrospect, I expect Elbaph will give us some major lore or give us more enlightenment on who Nika is as a god, and surely, their royal family must really hold some deep historical knowledge that they can pass on, I'd be surprised otherwise.
I do strongly believe Big Mom will end up being tied to Elbaph assuming she is alive of course.
