Nagato's power and mastery over Rinnegan is understimated, even Kishi held him back

[Ovan]

A lot of fallen ones would be stronger then the current living ones if they were not too old or too sick.

 

[KCMNaruto]

A lot of fallen ones would be stronger then the current living ones if they were not too old or too sick.

that is truth a lot of characters with wasted potential