Summary
The Straw Hat Pirates are an already accomplished crew in theOne Pieceworld, having recently been titled an Emperor crew. In Wano, they showed great growth as they successfully took down a Yonko, Kaido, and his powerful group of pirates in a very impressive manner. The Straw Hat Pirates are incredibly powerful right now, however, they still have room to grow, which just goes to show how frightening their potential really is.
RELATED:One Piece: Alternate Devil Fruits For Robin
As the story enters the Final Saga, it is now time for the Straw Hat Pirates to get their final power-ups and while some of them are simply minor upgrades for some characters, others are going to receive major power boosts.
9Usopp - Future Sight Haki, Armament Haki
Usopp is the sniper of the crew and he certainly is one of the weakest of the bunch. When it comes to battle power, he is certainly lacking, and in Wano, he certainly did not do enough to gain a power upgrade.
As such, he is one of the characters who is in need of a power-up the most. Usopp’s final power-up is most likely going to be Haki-related. Given that he is a sniper, gaining Armament Haki as well as the ability to see the future would be perfect for him.

8Chopper - Devil Fruit Awakening
Chopper is the doctor of the Straw Hat Pirates and certainly a skilled fighter. His Devil Fruit grants him several transformations that he can take, with Monster Point being the strongest. It hasn’t been explicitly stated if Monster Point is his Devil Fruit Awakening and fans will likely find out the answer to that in the Final Saga.
If that’s not the case, then Chopper will most likely receive yet another Devil Fruit Transformation, which will be his Awakening. This transformation would be his strongest state and offer him the best of all forms.

Nami - Weather Queen
Nami will most likely gain power-ups in the future ofOne Pieceas well. Given that her power-ups have always been oriented towards weather manipulation, she is going to gain an ability that allows her to further that skill. Nami recently got access to Zeus, which lets her manipulate lightning according to will.
She might get access to power-ups that improve her control over wind and other forms of weather manipulation. Zeus itself might also end up getting a significant boost in the Final Saga ofOne Piece.

7Brook - Underworld Frost
Brook is a character for whom writing a new power-up is going to be extremely difficult for Oda. For the most part, he seems to be reliant on manipulating the chill of the underworld after the timeskip.
It is possible that Brook will take this skill to the next level and gain incredible ice manipulation powers. These powers would be weaker than the Hie Hie no Mi in some regards, however, still significant enough to give him a strength boost.

6Franky - Battle Franky 39
Franky is the ship right of the Straw Hat Piratesand he is certainly quite powerful. He was able to defeat one of the Tobiroppo in Sasaki during the raid of Onigashima. His Battle Franky 38 was severely damaged in Wano and it is quite clear that there is a need for an upgrade.
With Vegapunk, he can develop a new version of this giant robot, and this model would likely be titled Battle Franky 39. Vegapunk could incorporate the mechanics of his own Vegaforce into it, making it very special.

5Robin - Haki And Devil Fruit Awakening
When it comes to the powerful fighters of the group, Robin certainly ranks among the very best. She relies on her Hana Hana no Mi in combat, however, it appears that she has taken this ability as far as she can.
Her final power-up will most likely be Devil Fruit Awakening andshe’s also in dire need of Haki.For a pirate as strong as her, Haki should be essential and that is most likely what she will end up receiving soon.

4Jinbe - Ryuo
Jinbe is already a very skilled and respectable pirate in theOne Pieceworld. He doesn’t have as much potential to grow as the rest of the crew, however, he is still going to grow further.
Jinbe possesses great mastery of Fishman Karate, and, as such, his power-up will likely not be related to it. It is possible that he will receive a Haki upgrade, perhaps gaining the ability of Ryuo, which would help him deal internal damage to his enemies.

3Sanji - Scientific Power, Conqueror’s Haki, Future Sight
Sanji is the cook of the Straw Hat Piratesand certainly one of their top three fighters. Sanji’s major power-ups seem to stem from the manipulation related to Lineage Factor. By the end of the series, Sanji will most likely receive more power-ups related to it and get stronger than even the Seraphims, who are labeled the strongest humans ever created.
Sanji will surpass them in terms of power as there are already hints for it to happen. Furthermore, he can also gain access to other skills, such as heightened Observation Haki that lets him see the future, as well as the ability to wield Conqueror’s Haki, since he is a Prince of a powerful Kingdom.

2Zoro - Asura With Haki
Zoro is already a master swordsmanwho is not all that far from his goal at the moment. He has received all the major power-ups that he needs to reach the very top. He only needs to bring out his very best and train them often.
Right now, Zoro needs to learn to control his Haki better since he cannot maintain his Conqueror’s Haki for long. Once he does that, he can incorporate this power with Asura, and that will most likely be his final power-up in One Piece.

1Luffy - Ancient Energy, Better Haki
Luffy has already reached his pinnacle as a fighter, as explained in Wano. However, there are still abilities that he can improve.Luffy still finds Gear 5 quite drainingand his control over this skill will only improve with time.
Furthermore, his Conqueror’s Haki Infusion is also relatively new to him and he can also improve in this aspect.

Most importantly, Luffy appears to have the power to control ancient energy, which seemingly stems from his own Devil Fruit’s Drums of Liberation. With this power, he was able to raise the ancient Iron Giant. Perhaps, controlling this power would be the ultimate power up for Luffy.