Well the Enton: Kagutsuchi seems to be a special feature of Sasuke's Mangekyo, while Itachi's special feature could possibly be the time-perception property inherent in his Tsukuyomi. Ideologically Itachi was an illusionary-lying character from the moment life put its grasp around him so his illusionary ability seems to correspond to that while Sasuke eventually developed into a character with a highly lethal and precise darkness, which can correspond to the Kagutsuchi.
I wonder if Madara and Izuna had special properties to their Mangekyos..... Tobirama knew about the Kagutsuchi so someone must have had that feature before, but who´s to say only named characters have had the Mangekyo Sharingan.....