Karnak's good, but he's never shown speed. his power is the ability to analyze the weak points in objects, but he has never really shown superior fighting skills/speed.
The KK owns him. hard in fact. its a good matchup in theory, if only the KK didn't show superior speed, much less fighting skills.
karnak would be fun against a guy like thing though. 😛 you're slow. WHAM. weak point, thing go down!