i don't think that is what happened ( itachi gave half of his power to naruto), if so, why kishi insisted in telling us that naruto's power is already huge even without the kyuubi, if so, why is the anime called Naruto if the main character depends of the uchiha??? if so why all that image of naruto's hard work and not giving up will of fire!!!
i really don't think itachi gave him powers, on the other hand i do think itachi realized, that he could die in peace because naruto would match sasuke's power to stop him somehow, it has been hell to itachi, living like that even someone that strong has his limits, i mean maybe itachi just gave up and let sasuke kill him!!! because you know you can't really become an hookage just with massive kage bushin and multi featured rasengan, it is needed more, and naruto it's still half of the way!!!
Honestly, sasuke is so weak minded, i mean does he never thought why madara told him that, or doubted about madara's story!!! God is so obvious that he will regret his actions, he lost his will, his feelings, he is just an enormous bag of power!!! and if i remember the firsts episodes of naruto showed us very well that the most strong power is when you use your emotions, like protecting someone, or team work !!!!!
so please somebody do something about sasuke!!! i'm just too tired of him