Just wonder... Shouldn't he have had the EMS in his left eye?
I can't really explain, but I'm assuming he's going to take Old Madara's Sharingan. According to Itachi, If the sharingan finds a new light they can awaken the EMS.
One of the gripes Itachi had about the Uchiha Clan, they would kill other Clansmen and take their eyes.
I mean, even if EMS was impossible... He couldn't awaken the MS of his replacement Sharingan?