sasue=elder son
narto=sage reincarnation
sage>>>>>>>>>>>>>>>>>>elder son
Sasuke is the elder son. Naruto is the younger son and the Sage. Arguing that because Naruto is like the Sage. Thus, he can't be the younger son is like arguing that the president-elect can't become president
Keeping with the surpass the generation theme, Naruto becomes the leader of the two. Thus, he is the younger son that becomes the sage. Naruto surpasses the younger son. Sasuke is the elder son that accepts Naruto as the Sage while sticking around to advise him. Thus, Sasuke surpasses the elder son.
Ten tails is a mindless beast. Tailed beasts came together a Juubi and are doing it for the second time, plus by going through with your prediction Kishi would be nerfing the fight of Naruto vs Sasuke that he has been pushing since Kage Summit. Logic and plot are against Naruto becoming the Juubi jinchuuriki.
I agree. Moreover, Bee and the eight tales and, more recently, Gaara and the one tail have gotten too much development to just leave their friends and be sealed in Naruto. With that development, Naruto becoming the 10 tails jin doesn't make sense. Why could Kishimoto waste all this time on development just to have them be sealing in Naruto with whom they have much less development.
The sage did not give his younger son, who was supposed to succeed him, the power of the 10 tails. Why then would Naruto (the Sage's successor) get the 10 tails? Finally, sealing the ten tails was temporary solution with the implication that Naruto would come up with a better solution.