Kingdom Hearts Characters overall strength Ranking System

This is an overall ranking that I give for all the characters in Kh so far, it may not be accurate as a diagnoses, but it's somewhere on that line.

I'm ranking each character's strengths by letter, and note that this is an major character ranking(as well as FF), Disney and heartless bosses will take place elsewhere.
But before I begin, I like to start by the characters that are not listed for multiple reasons, it's worth discussing about.

Characters not listed;
Namine
Kairi
Lea
Isa
Braignort
Isanort
Master Xehanort (Current)
Aerial
Ansem the wise's apprentice
Yen Sid
Young Mickey
Cid (Sid?)

Another thing to note is that I'm only going to rank Donald and Goofy based off of Kh1.
Okay let's begin~

D-
Sora(beginning of kh1)
Sophie
Tidus
Wakka

D
Riku(beginning)
Roxas (Kh2 beginning)
Hayner
Ventus (beginning)
Donald (beginning)
Goofy (beginning)

D+
Aqua (beginning)
Seifer
Digital Vivi
Teen Sora (beginning)

C-
Setzer
Terra (beginning)

C
Braig (Young)
Vanitas (first fight)
Donald (Middle)
Goofy(Middle)
Ventus (Middle)
Riku Replica (beginning)
Yuffie (Kh1)
Roxas

C+
Riku (middle)
Aqua (middle)
Xion
Vexen
Riku Replica (middle)
Demyx
Sora(middle)
Leon (kh1)
Zack

B-
Terra (middle)
Teen Sora (Middle)
Data Riku
Cloud

B
Riku (Darkness)
Teen Riku
Larxene
Leaxeus
Donald (end)
Goofy (end)
Tifa
Vanitas (middle)
Yuffie (kh2)

B+
Luxord
Sora (end)
Leon (kh2)
Pete
Data Sora
Braig (last fight)
Riku (Recom)
Riku (Deep drive)
Xion (Final)
Roxas (Zero gear)

A
Ventus (end)
Rikunort
Leaxus (Full power)
Zexian
Riku Replica (end)
Pre-Teen Sora
Malificent
Axel
Master Eriqus
Leon (Kh2)

A+
Saiax
Sora (Mark of Mastery)
Vanitas (end)
Terra (end)
Cloud (Kh2)
King Mickey
Ansem SOD
Teen Riku
Riku Replica (Absorbed Zexian)
Master Xehanort (bbs)

S
Marlixia
Xemnas
Teen Sora (end)
Aqua (end)
Saiax (Full Power)
Terranort
Vanitas (X-blade)
Maleficent (Final)
Seekernort
Dream Eater Riku

SS
Terranort (Final)
Xemas (DDD)
Young Xehanort
Vanitas (Lingering Spirit)
Seekernort (Final)
Marluxia (Final)
Riku SOD
Aqua (Current)

SSS
Ansem SOD (Final)
Sepheroth
Terra (Lingering Spirit)
Xemnas (Final)
No Heart
Armor of Master
Mysterious Figure

This is pretty much what I though of from the top of my head. There might be a few characters I might be missing, but I can already tell that you think this compression might be unfair, but remember, these characters are from different timelines and from time to time the character could get either stronger or weaker (Riku for example). And also, the strongest in the past can be as strong as the character in the present.
Discuss away~

 

Teen Sora? Sora's been a teen the entire game series, so kind of redundant to include that.

 

It's another way to call Kh2 Sora as Teen Sora. I try to avoid naming characters by game.