yes he is.kabuto said he couldnt dodge the sword in the manga and how can you say we dont know if its proven why would he ask for help if he could destroy it by himself ...hes not the type of ninja to ask for help unless he truly needs it
he's definatley the kind of ninja to ask for help he needed to make sure CT was wrecked, he is not a sensory type he can't tell how much chakra attacks posess.
you can't go round asuming theese things.
anyway in a one v one between itachi and nagato with out edo tensie itachi could easily tsukuyomi as nagato has no defence to genjutsu.