The philosophical case for why Obito was right and Sasuke is the new Sage
Obito (pre-TnJ) was of the idea that "there is no hope in this world" and that world conflict could only be ended by enslaving the TB. Hagoromo believed that Ninshuu would prevail and people could understand each other's feelings through linked chakra.
It's safe to say that Ninshuu as an ideology failed. Mankind desired war and power, and proved to be greedy in its nature. Even Hashirama was proof of that, as he himself weaponized the Juubi's Did I just call the First Hokage part of the problem? Yes, yes I did. Ashura too.
Ashura = good and Indra = bad is missing the point of the now blatantly obvious Ying-Yang Buddhist symbolism. Ashura and Indra balance each other and ultimately represent self-restraint and cooperation as an ideal. Obito's power clearly represented a more Shinto and animist ideal -- the use of raw nature itself and power to subdue mankind and it's relentless desires. Madara represents Indra's wishes -- belief in human power and in strength.
Ultimately Madara is the guy that wants to kill God here. He's the Gendo Ikari of the Naruto-verse. He wants to kill and replace Hagoromo and eat the god fruit to rule the world as an omniscient God. Obito just wanted to bring about world peace in a world of dreams. Why? Because in the real world, world peace is IMPOSSIBLE
Naruto wants people to believe in each other and all just be friends. Sasuke wants to destroy the TB and reform the system (notice we don't see what Sasuke actually says to Hagoromo's question) but the translation clearly says Sasuke, NOT Naruto, is chosen as Hagoromo's successor. Naruto gets the chakra of the TB. Safe to say Sasuke gets either Rinnegan or Ashura chakra upgrades.
In the end Naruto's approach would just end the same way Hashirama's did -- in absolute failure. The TB would be weaponized again. Sasuke's approach would cause political rivalries and alienate the weaker nations, causing more human-driven conflict. Madara ruling the world as God just causes mankind to lose any relevance or free will. Obito gives people what they want, what cannot exist in reality, a world of dreams and of peace.
Madara is a horrible final villain, Sasuke is the new Sage and Obito was right all along. My two cents.