Well, let's look at the last match. We have the Hero, who I have long advocated to be a peer of Anakin's, and then we have Kira Carsen--And I think I could make a strong case that Ahsoka could be her superior.
Ahsoka holds Anakin back. Look at rounds 4 and 5. Bariss and Ventress are both well above Ahsoka and would take her out faster than Anakin would defeat Nyriss or Shaak Ti. If indeed he would defeat either, since both are very powerful and incredible swordsman. Either of them would undoubtedly give Anakin a good fight and my money would be on Nyriss over him personally.
Also I could see RotJ Vader pwning them both with TK. He's far more powerful at that point than in RotS.
I don't see how Ahsoka would be above Kira. She's an Emperor's Child and she was able to fight through the Imperial Guard and Sith defenses on Dromund Kaas and she could partially tank one of her fellow Children's TK.
__________________ "Happiness is a lie. Life is horror. The light is always dying all across the universe. The last star will flicker out someday, when it does, all that remains is shadow. And I will be its king!"'-Amahl Farouk