Let's look at it from a strictly space control PoV.
From sweep (IE. the beginning of round 1) both Sonya and Kitana have excellent tools so they are even here.
From full-screen, Kitana has the obvious advantage with IaF, Square Ass, etc. If a Sonya player decides to get agressive and MS 2, F1 or B2 her way in, it's easy for Kitana to read this and thow standing fans to squash this or for chip vs dash blocking.
At point-blank it's all Sonya with her mix-ups, 50~50s and MS shenanigans.
The element of space control that tips this in Kitana's favour is that Sonya CANNOT LEAVE THE GROUND! If she does, she's eating massive unbreakerable damage and pushed back out of her comfort range.
So due to this and the fact that it really comes down to mind games from the players, I put this as 5.5~4.5 Kitana. As was stated earlier, whoever loses the life lead is going to have a loooooong night.