"The next generation always surpasses the previous one"
That was one of the dead themes of Naruto. Now it's been revived it seems.
It was but Kishi kind of screwed it up. Naruto and Sasuke are more powerful than Hagoromo and Hamura... bullshit.
If they had only their own power, they wouldn't have surpassed the original, first generation.
Yes, they might have surpassed the "previous" one but not the original.
It took all of tailed-beasts chakra + hagoromo's chakra for Naruto and Sasuke to fight on equal grounds with Kaguya.
It is really a big stretch to accept that Toneri could be stronger than Kaguya.