Board Thread:Naruto Discussions/@comment-1411686-20140815193400/@comment-1018594-20140815220723

The databooks usually give rankings of each shinobi's prowess. The last time one was issued, Jiraiya and Itachi were tied for strongest: 35.5 out of a possible 40. So by the time you get to around Obito and Madara, the scales become wildly irrelevant, kinda like the power levels in Dragon Ball Z.

But aside from that, we pretty much know all about the characters that we need to know by now. Kishimoto's not concerned with letting us know what Kaguya's favorite food is, or how tall the Sage of Six Paths is.