I have a theory regarding their power ups, Sasuke's in particular.
I believe that the only thing the sage gave Naruto and Sasuke was his senjutsu and the yin and yang seal.
Naruto on his own befriended the beasts and in turn they lend him his power, completely separate from what Hagoromo gave him; with this he was able to survive the bijuu extraction.
Now I believe that Sasuke would have awakened the rinnegan even if he didn't meet hagoromo. He obtained Hashirama's chakra, as well as his cells when being healed by Kabuto. Not only that but he was exposed to senju dna for the three years with oro and even sucked Karin's chakra for all that's worth.
Remember how Madara obtained the rinnegan when placing Hashi's flesh on his wounds? Only NEAR death did he obtain the rinnegan.
I believe hagoromo's senjutsu acted as a catalyst to speed up the reaction and quickly awake the rinnegan. And because of that influence, that may be why Sasuke has awakened one with tomoe on it.
I believe that the only thing the sage gave Naruto and Sasuke was his senjutsu and the yin and yang seal.
Naruto on his own befriended the beasts and in turn they lend him his power, completely separate from what Hagoromo gave him; with this he was able to survive the bijuu extraction.
Now I believe that Sasuke would have awakened the rinnegan even if he didn't meet hagoromo. He obtained Hashirama's chakra, as well as his cells when being healed by Kabuto. Not only that but he was exposed to senju dna for the three years with oro and even sucked Karin's chakra for all that's worth.
Remember how Madara obtained the rinnegan when placing Hashi's flesh on his wounds? Only NEAR death did he obtain the rinnegan.
I believe hagoromo's senjutsu acted as a catalyst to speed up the reaction and quickly awake the rinnegan. And because of that influence, that may be why Sasuke has awakened one with tomoe on it.