If anyone is interested:

1) My Straw Hat tier list.

S : Luffy

A : Usopp, Sanji

A- : Nami, Robin, Zoro

B : Brook, Chopper

C : Franky, Jimbei

Here is how I rank them. I pit them in several categories and see which one shines in a lot of categories.
Category 1: Character Development
Character development here is not to be confused with character progression. Character developments associates with how well the character’s personality, background, backstory, family, motivation-action realism and etc are.

1st place: Luffy

2nd place: Sanji

3rd place: Robin

4th place: Usopp

5th place: Nami

6th place: Zoro

7th place: Brook

8th place: Chopper

9th place: Jimbei

10th place: Franky

Category 2: Character Progression

Character progression here is not to be confused with character development. Character progression associates with how much the character has grown in terms of character personality during the course of the story.

1st place: Usopp

2nd place: Nami

3rd place: Robin

4th place: Luffy

5th place: Chopper

6th place: Zoro

7th place: Sanji

8th place: Franky

9th place: Brook

10th place: Jimbei

Category 3: Epic Moments

Not to be confused with sad moments / comedy moments, epic moments here refer to great scenes which bring people to awe of the action the character bring. There is a lot of weightage here for shonen audience as that is the main attraction point of shonen.

1st place: Zoro

2nd place: Luffy

3rd place: Sanji

4th place: Jimbei

5th place: Franky

6th place: Usopp

7th place: Brook

8th place: Robin

9th place: Chopper

10th place: Nami

Category 4: Sad Moments

Not to be confused with epic moments / comedy moments, sad moments here refer to great scenes which connects the audience empathically with the emotional/physical burden the character is overcoming. This is also a two way interaction, that means for example in scenes like Robin claiming she wants to live, Luffy is also included in that count, since Luffy was the one Robin was interaction with it.

1st place: Luffy

2nd place: Robin

3rd place: Sanji

4th place: Nami

5th place: Chopper

6th place: Brook

7th place: Usopp

8th place: Franky

9th place: Jimbei

10th place: Zoro

Category 5: Comedy Moments

Not to be confused with sad moments / epic moments, comedy moments refer to meme scenes that brings people to laughter when you watch them.

1st place: Usopp

2nd place: Luffy

3rd place: Chopper

4th place: Brook

5th place: Nami

6th place: Sanji

7th place: Zoro

8th place: Robin

9th place: Franky

10th place: Jimbei

2) One Piece Arc Tier List

A: Enies Lobby, Water 7, Alabasta, Marineford, Arlong Park, Whole Cake Island

A : Dressrosa, Sabaody Archipelago, Skypiea, Wano

B : Impel Down, Amazon Lily, Fishman Island, Reverie

C : Drum Island, Jaya Island, Punk Hazard, Thriller Bark, Baratie

C- : Loguetown, Reverse Mountain, Little Garden, Romance Dawn, Syrup Village, Orange Town

Doesn't pass One Piece Quality Control : Whiskey Peak, Long Ring Long Land,

Straw Hats Powerscaling for me (up to Chapter 1015)

Attacking Power - How much damage can be dealt to the opponents
Durability - How much damage can be taken and still able to continue fighting. If taken out after taking the damage, not considered.
Power Flexibility - How much potential can the power be taken for utility use other than hitting an opponent, in defeating opponents that is not to be fought. (Getting through a lake/Climbing a mountain)

Monster Trio
Luffy

Attacking Power - S
Durability - S
Power Flexibility - C

Zoro

Attacking Power - A
Durability - S
Power Flexibility - D

Sanji

Attacking Power - A-
Durability - A
Power Flexibility - C

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Jimbei

Attacking Power - B
Durability - B
Power Flexibility - C

Franky

Attacking Power - C
Durability - C
Power Flexibility - B

Robin

Attacking Power - D
Durability - D
Power Flexibility - B

Brook

Attacking Power - D
Durability - D
Power Flexibility - C

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Weakling Trio

Chopper

Attacking Power - C
Durability - D
Power Flexibility - B

Usopp

Attacking Power - D
Durability - C
Power Flexibility - S

Nami

Attacking Power - D
Durability - E
Power Flexibility - S