The problem here is that Kaumi cannot be used against moving targets as effectively as say if the target is standing still or heading straight for him. This is shown when he`s trying to get Diedara.
If Sasuke wasn`t weakened from using Sussano so much vs Danzou, I`m 99% positive that his speed is faster than Kakashi`s. Even then Kakashi said he was in trouble when Sasuke said can your burrowed sharingan extinguish that as he used a fully developed Sussano.
If you have an explanation for those two things then Kakashi may stand a chance. But then there`s still genjitsu, amaterasu, weaving hand signs as fast as Itachi, more chakara...
If Sasuke wasn`t weakened from using Sussano so much vs Danzou, I`m 99% positive that his speed is faster than Kakashi`s. Even then Kakashi said he was in trouble when Sasuke said can your burrowed sharingan extinguish that as he used a fully developed Sussano.
If you have an explanation for those two things then Kakashi may stand a chance. But then there`s still genjitsu, amaterasu, weaving hand signs as fast as Itachi, more chakara...