I would first like to state that there are a few things that make the StrawHat Grand Fleet different then most fleets we’ve seen so far

1- They don’t stay together the entire time, each division of Luffy’s fleet travels the New World on their own adventures which will help them develop in different ways.

2- They all joined Luffy not out of fear but out of respect

3- A lot of the individual captains/commanders have their own goals/dreams, they might not be as big or important as the straw hats but they are dreams

1 Cavendish wants to be a star and a great pirate known all over the world
2 Bartholomeo wants to be of use to Luffy and help him and the crew in every way
3 Sai wants to raise the happo navy to greatness
4 Ideo wants to be a great fighter kinda like Ussop wants to be brave warrior
5 Hajrudin wants to rebuild the giant pirate crew
6 Leo and co want to help Ussop and Luffy as much as Bartolomeo
7 Orlumbus seems to love adventure like Luffy

Now their potential growth is the main point of this theory

But first i want to bring up one of my theories on kings haki and haki in general. Now i believe the reason why we have not seen a Marine or any strong member of a Yonko’s crew with king haki is because they serve under someone, kings do not serve others. Also ranking systems are in almost every crew or organization in One Piece except the Straw Hats. In this way the Straw Hats are all on equal ground with Luffy, they do not shy from making their opinion known like in most crews, Luffy has been shown to take their advice when making important decisions like with Ussop on Water 7 and Sanji here on Zou.
With this freedom i believe that the Straw Hats and fleet members are not limited in how strong their haki can be trained and developed. I believe that the fear to constantly please and obey Yonkos like Big Mom and Kadio limits the overall power of someones haki because haki is a form of willpower and fear weakens willpower. In saying that I do not believe Yonko crew members are weak just not as strong as there maximum potential. The Straw Hats and fleet do not serve Luffy like most fleets serve there captains, they assist Luffy in his quest to become pirate king, this change in mind set can cause many of the main fighters to develop new attacks and unlock higher levels of haki like with Ussop when unlocked his coO haki.

Sai could improve his dragon drill tech adding the power to his staff gain kings haki like Chinjao.
What if Hakuba is Cavendish’s personal haki demon like the Zoro has and he learned to control him?
Barto could learn to crate more then one barrier and shape them into weapons animals or other shapes..
Others could develop spiritual power up like Sanji’s fire, Brook’s ice, Fishman Karate and unknown tech

Please let me know what you think below

*Theory by alwaysrollinup

First of all Croocodile is the first Logia-user that Luffy defeated.

Miss Goldenweek’s Rainbow Color Trap reveals that his dream was to become the Pirate King.

The soundtrack playing during Crocodile’s defeat is Dvorak’s New World Symphony, specifically the 4th movement, “Allegro con fuoco”. It was the third time in the anime when a piece of classical music was played in the anime (The first being Buggy and Gaimon’s farewell, during which Chopin’s Etude in E Major played, the second beingDr. Hiluluk’s last speech, during which Ave Maria was played and the fourth being when the zombies claimed Absalom as their leader, with Ludwig van Beethoven’s rendition of Ode to Joy).

It was noted that if the World Government had known Crocodile was head of Baroque Works, his bounty would be at least 162,000,000.

Crocodile is the first Shichibukai to be defeated by Luffy.

Crocodile is the only one of the original Shichibukai to possess a Logia Devil Fruit.

Crocodile shares some similarities with Doflamingo:

They are both former Shichibukai.

They both are/were leaders of a powerful criminal organization with several Devil Fruit users.

Crocodile was the main antagonist of the second saga of Part 1 (Baroque Works Saga), while Doflamingo was the main antagonist of the second saga of Part 2 (Pirate Alliance Saga).

They both are Devil Fruit users and have mastered their powers to high levels and both are aware that Devil Fruit powers can be awakened (in fact Crocodile was the first character to mention the concept of a Devil Fruit being awakened when he explained the Jailer Beastswhere Awakened Zoan Devil Fruit users while Doflamingo is the first Awakened ParameciaDevil Fruit user to be shown).

They both use coats as their common clothes.

They both were present at Roger’s execution.

They both aimed to control a whole country (with Doflamingo having succeeded).

They both contrabanded illegal sustances (Dance Powder and SAD).

Both characters’ defeats at the hands of Monkey D. Luffy seem to mirror each other:

Luffy defeated Crocodile by blasting through Crocodile’s single attack with a barrage of punches, launching him through an underground cavern and into the air.

Luffy defeated Doflamingo by countering a large group of Doflamingo’s attacks with one powerful punch, launching him through the air and into an underground cavern.

In the 5th Japanese Fan Poll, Crocodile is ranked the 15th most popular character in One Piece, making him the 2nd most popular of the original Shichibukai, the 3rd overall, and the most popular antagonist in the series. Coincidentally, 15 is the same spot he occupied in the first poll he was in.

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