Wait a second.
Why does "being privileged" even really matter?
IRL also the dudes who make it are genetically gifted.
Yes, they are also very much hard working. But without great genetics it wouldn't matter, hard work alone won't make it. That's the world we live in.
If you want to be amongst the best scientist, you need amongst the highest IQ (genetics).
If you want to be amongst the richest, you need amongst the highest IQ (plus being corrupt to an extend as well).
The best fighters, athletes will also have amongst the best physical genetics.
At some core level, it does explain why some characters in OP are simply stronger than others naturally.
What did teenage monster trio do to become the 3 strongest characters in east blue? Sure they trained, but training for childhood and teenage years alone won't make you stronger than adults you have arguably trained a lot as well, especially Arlong pirates who are fishmen on average 10 times stronger than average humans.
Luffy, Zoro and Sanji are all genetically "privileged" and it is OK.
That doesn't take away all the hard work they put, challenges they faced and dedication that they put in to reach where they are now (especially Luffy and Zoro) .
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Let's examine this a bit further.
Above was just me giving a defence of the genetics.
A major theme in one piece is also willpower and determination. Haki is materialization of these.
Willpower becomes your strength. You unbreakable will, determination, fighting spirit, hard work - they become your power.
This is further exemplified with the statement than conqueror's haki cannot even be trained in conventional methods. It just grows along with you, and if your fighting spirit gets stronger so will you conqueror's haki.
This is why 1026 Luffy had a higher conqueror's haki than 1010 Luffy, because his defeat increased his determination to take down Kaido even further.
This is why Zoro, who had only just awakened conqueror's haki, could materialize immediately conqueror's haki on the same level as Oden (albiet only for a limited duration of time).
This is quite fitting because it's quite a no brainer than Luffy and Zoro easily have demonstrated the strongest willpowers and determination amongst the new gen.
Now here is the issue though.
Even though Oda has linked conqueror's haki to "kingly ambitions/dreams" and inhuman willpower/determination multiple times throughout the series; he has also pretty much confirmed that you get born with conqueror's haki as well.
While in some level it could be argued that genetics does play a role in willpower, I hope we can all agree that willpower is amongst the most malleable aspect of a person.
In my opinion, conqueror's haki should've just been the manifestation of extreme willpower, ambition and determination.
This would fit perfectly into the kingly ambitions and determination thematic/narrative that one-piece/Oda is trying to promote, especially with conqueror's haki.
Instead of "only one in several millions just being born with conqueror's haki", it should've been "only one in several millions develop it because they are worthy of it"
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Coming to Luffy and destiny.
IMO the original (or inital) concept of destiny that was introduced/implied in the series was perfectly fine - the inheritance of will power!
This was what Whitebeard had explained in his final speech as well. An inheritance of will that isn't limited by bloodline either. Not all inheritors of Joyboy's will was D either, as evidenced by Shanks being one, and he is likely even a celestial dragon.
Let Luffy be the destined child, the child who inherited Joyboy's will through passage of the Strawhat. He, like those before him who inherited the Strawhat, became the destined child due to a strong willpower that they demonstrated.
My issue with the new concept of destiny is that it seems like the time and date were also important set through some prophesy. Roger couldn't enact Joyboy's will simply because he was too early.
Why and how does this fit in with one piece's core thematics - which is willpower, determination and dreams?
Instead of Luffy's DF being a normal paramecia that he made strong through his creativity and dedication, it turned out to be Joyboy's DF which is mythical zoan Sun God Nika.
And this DF had a will of it's own, eluded the near omnipotent and all powerful WG for 800 years, and chose Luffy to be the one who ate it. The implication from this is that Luffy didn't become the destined child, but was instead born as the destined child.
What really is the thematic/narrative purpose of this, and how does it fit with the thematics?
My problem isn't even really here that Luffy is from D clan, and especially the legendary monkey family of the D clan (two immediate ancestors being top tiers). Or that he has Joyboy's will.
After all, it is natural that top tiers have great genetics, the importance of D clan was long hinted, and the inheritance of will is a theme in OP.
It is that he was by birth destined to be this.
