Nagato saw his younger self in Naruto, the younger self who tried to follow Jiraiya's teachings. Nagato spend all of his adult life dismissing these teachings and turning his back on the world because he had viewed it's pain far more than any other, and he alone had the power to change it.as most people on here, your perception is surface only. It wasn't just that, he saw the power Naruto had and he believed in that as well, if Naruto was some weakling that Nagato could beat like hanzo, then he wouldn't trust him, but Naruto had the power, conviction and belief that he could change the world, and Nagato believed in that. So he sacrificed his life to revive the people who he killed in konoha and died to redeem himself. After speaking with Naruto, he was able to realize that his ways were wrong, there wasn't anyone up till then who resembled Nagato so much.
Then he found naruto, and naruto spouted the same words he himself had turned his back on long ago. There's no reason this should have had a profound effect on him. To Nagato, this should have been more than evidence enough that the world was as broken as he had seen.
If Nagato's dreams could be changed by a child who believed what he did once, he would have never turned his back on those words in the first place.
Nagato planned on forming a bijuu super weapon, to create a pseudo-Nuclear deterrent for the world, the same as we have in the real word. Did you forget that part?You said he had a decade spanning plan, when that's not the case since the plan was not his. All the trio wanted to do was settle fights through democracy until yahiko died.
Not even close to Obito's plan.