Well MS gives user 3 ablity! One is from left eye and one from right eye. And one when a person has both 2 other abilities. For eg. Itachi has amaterasu(physical) and tsukyomi(genjutsu) in those eyes and is able to awaken third ability(Sussano) and same goes for Sasuke and Madara. Sishui uchhia has both genjutsu related power one of them is the one danzo used to control mifune and next one is itachi used on himself. and obito's has both physical related power of dimension. so they would have different third ability(I know this is sure so dont argue about this one). What do u think third ability if kakashi take obito's sharingan?