Well , it should be like Kisame was afraid of him and even Tobi.tobi was afraid of him and even kisame
Disease didn't matter Itachi could beat sasuke anyways he let sasuke kill him to protect him and he wanted to die by only sasuke's hand.itachi.... if itachi dont have a disease then he will beat sasuke for sure. he have a lot of experience and smart. he can developed tsukiyomi. sasuke do nothing and just thinking about kill itachi.
Well sasuke knows how to use amateratsu and susaneo more than itachi's now. but itachi is better with Genjutsu.who is more stronger itachi or sasuke??