1: No. That pairing won't happen. Has there ever been a gay relationship in a shonen manga? Also, the Uchiha would die out. Sasuke wants to restore the clan.
2: Naruto is way too idealistic to end with the hero being killed by his best friend. By that same logic, Sasuke will get redemption. This doesn't allow for that. Also, Naruto's dream to become Hokage and reform the ninja world was pointless.
3: Naruto is too idealistic to end that way. Sasuke will be redeemed. Sasuke will restore the clan, or genocide will be condoned. Also the surpassing the previous generation theme will be forgotten since Naruto failed to save Sasuke just like the previous generations did (Hashirama and Kakashi).
4: Again, Naruto is too idealistic to end that way. Naruto's dreams would be pointless. Since all the Uchiha are dead, genocide will be condoned.
5: Itachi's sacrifice was pointless. Itachi was supposed to be teh darkness, so the Uchiha name wouldn't go down in infamy. Sasuke was supposed to be the light to reform the clan. He was supposed to surpass Madara by overcoming the curse of hatred and returning the village. If everyone thinks he is a villain, everyone will hate the Uchiha because Madara, Obito, Itachi, and Sasuke. Itachi's sacrifice to preserve the clan's honor would have been in vain.