what are you talking about? Of course sasuke will know if kakashi is underground just like he saw deidara's mines, sasuke is not a 30% clone itachi... Just because a 30% clone itachi with sharingan couldn't see kakashi doesn't mean sasuke with ems can't. Stop comparing them it's kind of annoying! Sasuke has demonstrated he could see underground attacks with a 3 tamoe sharingan so ems would do way better and that's final! :scorp: counter chidori nagash with his raiton attacks?? Care to elaborate??
30% clone Itachi had all his technics. Pain said that his clones where perfect. They can do all what original can do. The only limit is chakra. It's what you're saying which is pretty annoying. I show you that Itachi with his sharingans couldn't, so why do you think Sasuke will? EMS or not, that doesn't show he will. Pain has Rinnengan(much powerful than EMS, which could even see konohas barrier, who is even a sensor type), but he didn't notice Kakashi was hiding, he didn't notice that the kakashi he was fighting was a raiton kage bunshin.
When will you finally take a look that Kakashi had already fooled Sharingan and Rinnengan and that he can also fool Sasuke too??
3tomoe sharingan was able to see chakra underground because he had time for it. Kakashi will not even let him time to notice that. He will leave a clone and go underground as always. When Sasuke will fight the clone by thinking it's the original he will be underground and will attack quickly. That's how Kakashi fights.
And for the chidori nagashi, as i've said, Kakashi could counter it like he managed to counter the raiton gian from Kakuzu. If you begin to imagine such a thing, i can also say that Kakashi could use lightning wolf and Sasuke couldn't counter it.