Are you sure guys? In my opinion, Savage's duels with Ventress, and Plo were much more equal then this one with Kenobi.
Kenobi best Savage, when he was aided by Maul. Maul should be in the same league with Kenobi, or even higher, because of his superior force skills.
Savage had a small advantage over Ventress, but she had just one saber. With two, it might looks quite different.
Savage dueled Koon, and he had small advantage.
Ventress dueled Fisto equally, and finally won. On the other hand, when she dueled injured Koon, she still was unable to tak an advatage. In fact, advantage was on Koon's side.
So:
Kenobi > Opress
Ventress >= Fisto
Ventress < Koon
Opress >= Ventress
Kenobi >= Ventress
Opress >= Koon
Smth like that? For me, only Kenobi have clear advantage over most of them. Maybe the key is, to rank people from tier 4? Savage would be on top. But I'm still not convinced, to put Ventress into a higher tier then Plo's.
Or, maybe smth like that:
Tier 3: Kenobi, Maul
Tier 4: Ventress, Opress, Koon, Bulq
Tier 5: Kolar, Fisto, Tiin, Billaba, Bondara
Tier 6: Ti, Drallig, Mundi, Koth
Still, I have a doubts about Sora in that way. His duel with Mace was more equal then Savage's with Maul or Kenobi.