Well I would absolutely love it if kishi does in fact allow events to be influenced by foreseen (by the reader) or unforeseen actions by way of kabuto's precautions and sheer genius. The manga could use, IMO, more instances of brains over brawn that lasts longer than stroking the crux of a single battle. I become more interested in kabuto everytime madara advances in this battle because kabuto struggled harder with less direct advantages than the sharingan but reached an impressive level so far in his way of becoming the next rikoudo.
The poison you reminded me about gets me even more hooked and looking forward to kabuto having a prominent third position in this struggle aside from the obvious two ways of the bloodlines. His accomplishments and unique angle are a good contrast to senju vs uchiha and would be welcome in the mix that has been running risk of uncontrollable near cosmic power. Orochimaru, by being surpassed by kabuto has been relegated to a different role and position which should facilitate sasuke's development.
The final struggle, yeah, will it be sasuke and naruto harmonizing and knowing how and when to rely on each other even to the point of fractions of a second maneuvers within a shinobi battle against the final boss or will it become a matter of who sacrifices what to empower the other.
Anyway, without getting ahead and staying on topic, the sharingan itself would be an intriguing means of Madara's undoing. With obito becoming a wild card and talk-no-jutsu setting in, i really want to see the kamui pair of eyes reach their potential in this unique way of two casters yet also a strong bond the likes of which the manga makes a point to stress. More than a few of us, I'm sure, half expect kakashi and obito to permanently seal madara in the kamui dimension (which i still believe is the moon). It would be even better if obito warps himself into a solid structure in the kamui dimension, a solid structure with possible.sealing qualities but brings madara with him to be locked in the same structure and bound by the edo tensei rules so he is in permanent regeneration but it can never complete because of the loophole of physicality being warped into solid matter causes. Obito might die but would be poetic sacrificial atonement. Especially if kamui is confirmed to be the moon/sealing stone of the juubi's body.
Another cool possibility is once obito reestablishes his bond with kakashi they can awaken susanoo! They might both be in close proximity /back to back to form it or better yet, according to idea of relationships and reliance on comrades, they each get half susanoo power, one offense characteristics and the other defense characteristics. Not sure how such forms would appear or if each would take the appearance of "half" the same way zetsu and obito himself show but it would be very thrilling and exciting tag team combo combat for a few chapters.

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