You are so right. In order for the cycle to be destroyed, Sasuke has to die. Refusal to do so on Naruto's part would be irresponsible at this point. The shinobi world should not have to suffer the consequences of an unstable psychopath just because a future hokage has abandonment issues that prevent him from making the tough decision of putting his "friend" down like one would for a sick and dying pet.
I say "friend" in those quotation marks because Sasuke never really had a friendship with Naruto, Sakura or anyone else in the Leaf for that matter. He wanted nothing to do with them and only care about avenging the honor of his clan against whoever the kitten happens to be unfortunate enough to be the target of his childish rage at the moment.
But what about Taka, some people might say. What if they want revenge for Sasuke's death? First of all, Taka alone doesn't have the manpower to conduct a full scale war against the Shinobi Alliance nor any demographic advantages necessary for such a war because public opinion doesn't view Sasuke and his cronies in high regard. Plus there's the fact that Sasuke doesn't really have a model relationship with his supposed allies.
Orochimaru just wants to take over his body to gain the power of the Sharingan, Jugo is just following Sasuke around because of his blind devotion to an ill man who was blindly devoted to Orochimaru enough to be a pawn of his, Karin is just a pathetic Sasuke fan-girl who posesses the same mentality of Twilight fan-girls and real life women who have crushes on mass murderers based on the fact that they find said mass murderers attractive for whatever kittened up reason that they may have and Kabuto would just be a rogue agent no matter if he turns out to be still evil and out to get power or if he terns out reformed enough to reunite with his old orphanage buddies anyways. So helping out Sasuke go down further on his evil path would be out of the question for a Kabuto who is now on the side of good if he were to be truly reformed from his evil ways. Suigetsu wouldn't give a kitten about Sasuke anyways since he only followed him around to further his own goals of getting all of the Seven Swords of the Hidden Mist to become it's new leader despite his arguable success rate of even doing so in the first place.
Sasuke has nothing left. His closet thing that he can personaly call his companions are all nutcases in some way that will either end up dead, in jail, in a psychiatric home, reformed or abandoning him when things get too rough and out of hand. Almost everyone in the Shinobi World would rather see his sorry ass dead and move on with life as if nothing bad has ever happened after Sasuke's possible execution. He's alienated anyone who wants to help him except for the ones he would discard once he finds no more use for their skills to benefit his agenda. He has isolated himself from the rest of the sane world and he only has himself to blame.
Naruto has to learn that he can not save every person from a horrible fate if they don't even want his help in the first place. He needs to let go of the past and keep going in order to shape a better future for the world.
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The only way that the Uchiha and Senju can truly live on is through the offspring of Kakashi and Yamato if they indeed end up surviving. Both are good enough friends that don't hate each others guts and would get along well with each other if they formed their own clans as successors to the Senju and Uchiha. Plus if Kakashi's kids inherit the Sharingan, they wouldn't end up as bloodthirsty psychopaths who can't handle loss. (I know genetics don't work that way, but Kishi has made mistakes in regards to science before, so if Amaterasu can be as hot as the sun without causing the entire area around it to become a melting uninhabitable death zone, then I'm sure Kishi could hand-wave two guys with another clans' abilities passing on said abilities to their non-uchiha or non-senju children as the Uchiha and Senju DNA being that powerful.) I know that Kakashi has had hardships in his life, and that he awakened the Mangekyo when he killed Rin. (Along with Obito who happened to witness Rin's death right in front of her.) But the thing is, he never really sought out revenge against anybody just to take out his frustrations on them. He has the mental fortitude, sense of character and the moral code to cope with his losses. Granted, they still haunt him to this day, but at least he knows how to deal with it and still keep his sanity intact. Which is also impressive considering the fact that no one ever seems to see a therapist in the Narutoverse. The Leaf wouldn't have to worry about another Madara being born within the ranks of Kakashi's family because Kakashi would be able to instill a familial culture of accepting life's hardships and coping with them as well as ethical codes to follow to counteract the dark side of the Uchiha clans bloody past that bred a culture of uptight warriors who could never understand how to live it down with other people and just let their feelings dictate their actions.
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