Just some thoughts...

Currently I see alot of people who think that Sasuke's role in the story is turning the table and finding a way to beat Madara and stop the moonseye plan with Naruto.

Normally I do not agree with that but I thought about it alot and had the following idea:

This theory has nothing to do with the story itself. It's more about what Kishi might think and plan (who knows).

We all can see that Itachi is a tragic character. Alot of people might already have forgotten him and call him 'fodder'. Still he was a great addition to the story, a deep character with an interesting development.

What we all think (even Itachi himself thought so) is that he sacrificed alot to protect his village and brother but all he did was a failure. His plan didn't work, he couldn't stop Madara so we currently have that horrible situation and no one can stop it.

When all that Itachi did was useless and a failure, we can pretty much forget about it but what if what he did will lead to the ultimate change? What if Kishi wants Sasuke to really find the only way to stop and destroy Madara which would save the world? At this point, all that Itachi did was the right thing and not a failure.

Question is, as unrealistic as it may sound, will Sasuke cause the decicive change, just so Itachi's sacrifice wasn't all for nothing? Could that be Kishi's plan? I'd like that one since it would give a great character a great meaning. And not make him disappear into meaninglessness like K11 and the kage. I still hope they will play a good part but it looks doubtful.