you know if they can give us X episodes of Madara talking to Sasuke. Why can we not have Kakashi talking Sasuke down.

I'm still a bit sad that we will never get the Kakashi vs Kabuto great fight after they have simply dismissed Itachi and Orochimaru. I'll never forget episode 55ish where Kakashi delivered that great line to Kabuto are you going to keep running from me or whatever. I feel robbed for remembering it what 4-5 years later and still clinging to that as a promised battle.

Can someone explain to me if there was something really wrong about Itachi did he have some kind of ailment(cancer?) or Was he possessed by something else that caused him to not fight in top form. Do I trust what madra said how its all plotted out. So it was all a lie about needing second set of Sharingan eyes? Or why was Itachi really losing his eyesight?