As an advanced Commander player, I feel that I have a proper grasp on the power potential that each color combination and, more specifically, each Commander has. I've decided to put my opinions onto paper (internet paper). Please let me know if I've missed anything obvious or yell at me if you think I'm wrong about something.
S Tier
5 Color Combo
Derevi, Empyrial Tactician
Sharuum the Hegemon
Zur the Enchanter
Animar, Soul of Elements
The Mimeoplasm
Jhoira of the Ghitu
Edric, Spymaster of Trest
Azami, Lady of Scrolls
A Tier
5 Color
Bant
Esper
Grixis
Naya
Kaalia of the Vast
Rug
Ghave
Bug
Azorius
Dimir
Captain Sisay
Teysa, Orzhov Scion
Izzet
Simic
MonoBlue
B Tier
Jund
WBR
Junk
America
Lyzolda, the Blood Witch
Golgari
C Tier
Orzhov
Boros
Selesnya
Rakdos
Gruul
MonoBlack
MonoGreen
D Tier
Mono White
Mono Red
I'll probably add more tiers later, but I felt this covered most of the basics. Again, let me know what I missed