Nami is Uranus. My pet theory.
Honesty, Sanji had a more closed-ended backstory than Nami or Zoro.
Second theory, Tashigi is Hiiyori and will be in the Wano arc in later parts. Komurasaki is a red herring to throw us off but was just Kyoshiro's sister or something whom he had to live a tough life with in the Red Light District, and he would rather slay her than have her get slowly chewed on. Or faked her death. Or Tashigi is Zoro's lost friend and there's some as yet unrevealed plot behind it. Gotta be something going on with it. And Oda had this in mind since Loguetown, too.
But back to Nami. Compared to Sanji at Baratie and Zoro's backstory, Nami is very odd. She and her sister arrived with Bellimere, who quits being a Marine. Do we even know if she deserted? We assume it was honorable, but it almost sounds like she was presumed KIA after some kind of battle. Nami definitely had parents somewhere in the past. Why are they not mentioned? Why has she not remembered ANYTHING? Even snippets? Shew as very young, yes, but where did she come from? Her abilities to control the weather are also odd. They give her a natural talent that should be impossible. Vivi's telling statement was that Grand Line Cyclones were impossible to predict, yet Nami fundamentally knew immediately when there would be one, and when she was down with fever to boot.
In fact, there was no way for her to have sensed weather changes from inside the ship, but she did anyway.
If not for the weather issue, I would guess Nami to be a Celestial Dragon that was presumed killed at early life and thus never looked for. I almost expected Reverie to give us a hot female Tenryuubito who obviously resembles Nami... (although most beautiful women in OP now resemble each other, especially post time skip, so that is not saying much. But still. Oda could do other things, like give us a Nami moment where one of them freaks out over a dropped penny and threatens to shoot everyone around her if they dare touch it, or such)
The addition of the weather phenomenon adds a monkey wrench. It is Nami's theme. Is it just her special ability like with Zoro's durability? But Sanji had unbelievable durability way back in East Blue. He survived his fights with Don Kreig's crew, and then battle underwater against a Fishman from the Grand Line, and he won. That was impressive. It was obvious he did not have a normal physiology. And made constant small references to being a prince. Smart readers caught on, most just scoffed, I was one of them. Mockers mocked. And then boom. Germa 66, rulers of ALL North Blue, the strongest of the four blues.
So yeah, Zoro could very likely have a reason for his inhuman power. And if that is true for him, so it could be well for Nami. Her past is open-ended and frankly I see no reason for Oda to not have planned out something, even if he was just trying to be mysterious. Nami having just been found out lost at sea is too much. She do be Uranus or indirectly related.
Specifically: She is to Uranus what Shirahoshi is to Noah.
In that same vein, another crazy theory! the Nefertari family actually keep the secret of Pluton buried because they have a relation with it. So Vivi would be to Pluton, the ship, what Shirahoshi is to Noah. Yes there are great battle ships, but there is another, living component. In Poseidon's case, it requires a Mermaid Princess who can command Sea Kings. She has Noah to ride in. Some may be the case with the other two ancient weapons. Perhaps they were not meant as weapons at all, but as something else. Perhaps that is the true reason for the WG's fear of people learning the truth! It is because people will learn the long demonized superweapons are in fact not weapons or destructive inherently at all!
That seems to contradict what we have seen, and Pluton appears to be a real superweapon by the way Franky reacted. Could also be he simply did not fundamentally understand at what he looked. We never did see what Pluton looked like. It could look like a freaking Flying Saucer! Or at least something totally different from the standard. That would explain how when Franky showed the plans to CP9, those who worked at Galley-La stared in shock and disbelief. They were silenced by what they saw on paper and knew it to be genuine. I don't recall Spandam's reaction, but he's not a reliable source for anything.
So with Nami, perhaps she has an inherent relationship with the weather. I always suspected perhaps Enel and the Ark were actually Uranus, and Oda just did not tell us. That would explain how Robin knew about the Goro Goro no Mi. She read about it on a Poneglyph. But it is strange she wouldn't have mentioned that the ship plus Enel equaled an ancient superweapon (even though it displayed such powers and was related to the weather, which is confirmed for Uranus, yes?)
Not sure. As with the Enel bit, there all sorts of possibilities. But that's why I am posting it here with the crazy theories.
Oh, and Linlin ended up with Amnesia. That was one others speculated would happen way back in WCI. Though I thought it would be opposite... guess she will remember things from the start up, and her recollection of what became of Caramel will send her flying to the giant's island Elbaf to learn the truth.
Your Nami theory is really cool, I like it. Just to clarify though I am basing my response in part on a youtube video which claimed each Superweapon is based on a type of Haki.
So it's not all my own original idea. But I think i can come up with at least a few original and helpful predictive observations here.
If Nami is the reincarnated destined user of Uranus, it would make a ton of sense if Uranus was Observation Haki based as this guy speculated, with Pluton being Armament Haki related and Poseidon obviously being Conqueror's Haki based. That could relate to Weather as well as Nami's penchant for Navigation and showing everyone where to go/'predicting the future'. Nami's weather powers will matter in other ways in my opinion and Uranus isn't directly related to Weather in what it specifically does. Although it could well be meant to be used in combination with a flying ship, i don't think it is right now, based on this theory. How would it be weather related if it's based on long range future sight and possibly also long range remote viewing of distant places? Maybe it was originally meant to predict weather patterns and help protect people from the dangers of the sea and the weather, even though it could also be used as a weapon in war to predict where enemies will go and what they will do. Then, in combination with a Weather Weather Fruit, Uranus could be used to very efficiently manipulate the weather and make sure everyone prospers by it rather than getting destroyed by the chaotic nature of the seas, especially the Grand Line seas.
Btw, I have an original little hypothesis that Nami will one day obtain a Weather Weather Fruit which i think Dragon has right now(based on him saving Luffy at Loguetown from Buggy's execution) and Roger might've gotten at some point while he was alive. As possibly evidenced by him seemingly 'getting lucky' and having Shiki's whole fleet be sunk by a giant storm when they clashed. He could have simply summoned that storm with his weather powers. He could have hidden from the world that he had a DF ability to preserve his advantage and it is not like they have the internet to spread every little bit of info about him. At one point in the chapter"Roger's Adventure" he says he thinks DFs might be a myth which seems like big contrary evidence, but there were many timeskips in that summary chapter. He could have obtained the Weather Weather Fruit at some point in between panels offscreen without Oda notifying us that he had changed that view. Oda misdirects sometimes, i don't think he wants Nami's future DF to be spoiled too easily.
Nami getting Weather powers directly fits with her already having stolen Zeus and being foreshadowed with basically supernatural weather manipulation/prediction powers early in the story like you said despite not even having a DF at the time. Her first introductory chapter, chapter 8 made it look like she summoned a storm to sink the boat of some pirates that she had just stolen from with how it was framed, and the way she did that was by somehow predicting the exact time of a storm and arranging things so she would escape with their goods and the storm would stop them before they could get her. So it seems very foreshadowed that one day, Nami will be casting thunderbolts from the heavens for real and manipulating the weather itself lol. One day Dragon will die in the revolutionary war and Nami will inherit his will as the one who the revolutionary army maybe allows to get his fruit from the nearby area where the fruit must've reincarnated. Or she just gets it by luck/destiny after he dies or something. But i feel like it's definitely gonna happen that she gets it.
The theory video says 5 minutes in that Enel's Observation Haki was also foreshadowing that 'God'(The WG, who he represents in Skypeia, which is maybe a mini arc representing the whole story) has a method of Omniscience that they regularly use to rule the world with an iron fist. This would explain why Imu somehow knows what lights need to be erased from the world, routinely does so, and hates Luffy and co so much even though they don't seem like a big threat early on. So 'God' would be the immortal Imu-Sama monitoring the world and the future via Uranus, which he probably has right now. So how could Nami ever get Uranus?
By stealing it, of course! Hooray for Nami's theft skills.
Now this guy says the Giant Straw Hat in Mariejois is very important to the plot and might be the sacred treasure of Mariejois. One of the two things that could make it so important would be if it granted great power if worn, but that doesn't make sense since it's too big to wear, even for Imu. But the last option he said is, what if it's not just a Straw Hat? What if it's Uranus and changes shape to show what's the most dangerous to the user? And that's why the Straw Hat is so big, since Luffy will be a giant threat to the world government in the future?
In fact, my little interpretation of that idea is that Uranus could be some sort of magic haki technology crystal ball like thingy that projects a hologram, and it projected a giant Strawhat hologram around itself because Luffy will just be that dangerous to the WG, while anyone who actually looks at the ball itself and has observation haki might get detailed visions of future events rather than generic warnings alone. We just can't see Uranus because it's hidden by the hologram thing it projects. As the theory guy said it could also be that Imu can control what he sees with Uranus to an extent, but the future he is constantly trying to predict is usually Luffy's, since Luffy is the biggest threat. He could still be trying to foresee the futures of other big dangers to the world government. It would make sense as a result of Imu-sama has super advanced Observation Haki which is what qualifies him to use Uranus. Nami would just be the destined user of Uranus, but others with strong Observation Haki could still potentially use it, just as Shanks was able to use his Conquerors Haki on a seaking despite not being the destined Sea King commander Shirahoshi.
Pluton would then fit as the armament haki type like the guy said, although i am pretty sure it does actually use Haki itself and doesn't just have a similar function through explosives or something. I think Blackbeard might steal Pluton in the future because of the mythological foreshadowing and other reasons. He uses darkness powers based on stealing DF powers which basically involves sucking the 'Devil'/soul which gives the DF ability out of the body, 'steals souls' sort of with his crew taking DFs(probably by eating hearts) and already himself probably has three souls inside him including his own. He has killed tons of people, and he also has a Quake Quake no Mi now which is based on the Earth and Earthquakes, fitting the Underworld theme. So the 'god of the underworld' thematic thing would fit for what is going on with Blackbeard and obviously the weapon he would try to steal the most is Pluton, the one that would let him blow up islands. Plus, it is foreshadowed that the Alabasta treasure is Pluton and is buried deep underground fitting the underworld theme and Blackbeard is doing stuff to try to seemingly get Sabo's DF after the scandal incident surrounding Sabo and something Sabo did. So it is entirely possible that Blackbeard's superhuman Luck will kick in and he will end up finding a convenient opportunity to get Pluton out of Alabasta. It is buried underground, but that is probably no problem. He might force the people of Alabasta to give him the weapon with the threat of his tsunami powers or just directly break into the underground spot where Pluton is himself with the Quake Quake no Mi. Honestly i don't know how any of this would fit with what i was predicting about Blackbeard showing up in Wano to steal Kaido's fruit and how any of that could tie together, but who knows. I'm not going to try too hard to predict everything in exact specifics, I just feel like Blackbeard will try to steal Pluton at some point or another. And he might even be the destined user of Pluton. Although it could probably also work if he just stole it even if someone else was supposed to get it instead. BB is not a particularly good Haki user due to his significant fear of death, so that might not fit this idea 100%, but in other areas, it would make sense for him to steal it, even if the direct user who powers it up with Haki might be someone else on his crew who is stronger at Armament Haki, like Jesus Burgess or something. I just feel like it would fit the story direction Oda seems to be going for, although BB may die at some point in the story and get Pluton either stolen or destroyed by the WG or the Strawhats.
Plus, BB can already destroy islands with earthquakes, yeah, but with Pluton he would be much more dangerous as then there would be 2 island destroying super weapons under his control as long as he isn't always sitting on top of Pluton all the time. And Pluton may be the only super weapon capable of blowing through the Red Line, something which will probably be very important in the story.
But overall the thing I am most confident about is that Nami will steal Uranus from the WG at some point in the story and use it, eventually in combination with a Weather Fruit. And that Nami is possibly the destined reincarnated user of Uranus like you said, just like with Shirahoshi and Poseidon. And that Uranus involves Future sight/long range remote viewing of the world or something. Future sight is probably the main thing though.
Bonus evidence that Uranus could be future sight came from a comment someone made on that video, that the titan Uranus in mythology saw the future of his own defeat by his sons, so the connection is there between Uranus and precognition. And it also fits Nami's character as the team navigator for her to get this treasure. Her stealing Zeus from Big Mom seems like both foreshadowing for her doing this bigger theft later and possibly also for her one day getting Dragon's Weather Weather Fruit. Once Luffy and his nakamas reach Raftel, they could easily learn the current location of Uranus from a story written down in Raftel of Uranus being stolen by the WG, and the truth about Imu and all that he did in the Void Century. Which would lead them to easily deduce that it must be in Mariejois right now if they are told Imu-sama is super powerful and would therefore be waiting in the most vital place in the world for WG in case a big threat shows up, to be sure he will always be ready to defend it, and because he is secretly ruling the world.
Also, about the Uranus future sight of being killed by his own sons:It all fits the Nami is a Celestial Dragon idea you have! If Nami is descended from the 'gods'/Celestial Dragons ruling the world it all fits, and maybe she is even a very distant descendant of Imu himself lol. Either way it would make it so Nami is the 'Zeus' to Imu's 'Uranus' and is destined to rebel against Imu and overthrow him/steal his Uranus super foresight artifact. Plus, Nami has literally stolen Zeus from Big Mom already so IMO this hints at her role in relation to Imu in an even more direct way lol.
I am sure Imu will be very powerful as this is a shonen, and while Imu could easily just be a political secretive immortal ruler and still be very important as a result of all that, it feels very appropriate to me for him to be a strong enemy Luffy will need to beat up some day to free the world. So all of that would make predicting Imu's current location easy for them, not that it would exactly make defeating him or stealing Uranus easy in any way.
I don't really know how Enel's super spaceship could connect to Uranus, although i think it could be a good idea. It could be that it is like a more advanced version of Pluton since it uses his lightning to power it and make an island busting super explosion. Or Pluton may also be able to fly like Enel's ship, as long as the haki user is strong enough, or the DF ability works for flight. It may be a pure haki based weapon, or it could also be a DF ability enhancer. Armament Haki is more likely imo as the power source and way the weapon works but maybe DFs are a possibility, seeing as how Enel powered his ship with lightning. It could just be that lightning is close enough to haki for him to power the ship directly with it, or that Enel's ship is a specialized variant of a Pluton type ship which only works with one specific DF, but who knows. I do feel like there is a possibility of a connection there. Maybe the Ancient Kingdom once used Enel's ship as a flying ship in combination with Uranus and a Weather Weather Fruit user, to deliver good weather all over the world easily by going from island to island with their flying ship and etc. What was the positive non harmful purpose of Pluton? I don't know to be honest:Perhaps the main purpose was just that they wanted to blow a hole in the Red Line and they absolutely needed a super weapon like Pluton in order to do so, but the other two were probably not intended as solely weapons at all. However, if Pluton can enhance any DF ability to a super big level, and not just Armament Haki itself, it could have had other purposes. Imagine the Heal Heal no Mi turned up to 100x the power level and used on an island of sick people. That would be a pretty great positive result. They also could have made artificial islands with some of the other Devil Fruits like Big Mom has already had her suboordinates do with their food based DFs. Heck they could even create food to an extent as long as they have appropriate DFs. They could do a lot of really useful stuff in other words and the sky is kind of the limit when it comes to that. But even if it is just Armament Haki based, it is not like having a super powerful weapon is bad if it is the only way to break the Red Line and unite the seas again. If anything, they probably refused to use it against islands with innocent civvies on them and lost the war partially as a result of that, fearing a nuclear war style arms race more than anything else, which may have happened if they mass produced Plutons and WG inevitably learned their secret and started ruthlessly using Pluton ships to blow up islands of the ancient kingdom.
Ancient Kingdom may have also had Pluton used on them and had many of their islands sunk to the bottom of the sea. Maybe that is part of why Alabasta has sealed away what might be Pluton underground and why their king in the past was the only one of the WG's 20 kings that refused to live in Mariejois. I don't know, i have no real evidence about how Pluton was used but I do think the Ancient Kingdom hesitated to use it in too warlike a way, and i think many people have also speculated this in the past.
Anyway that was a pretty cool and interesting theory to read, I do think you are right and Nami has a connection to Uranus. This kind of snowballed into a whole lot of stuff rather than just talking about Nami but i hope it wasn't too much of a wall of text.
Final bonus Nami trivia, I think Nami is probably an anagram for 'Mani' or in other words 'Money'! No wonder she is so obsessed with money. Lol.