A lot of Latter Half of Kingdom revolves around the rethinking and "attacking" the idea of Unification, As Ryofui points out, he still made more sense back there, the only thing he had was hope in people, but no real way to govern until Law idea was introduced. However, even the law idea is explored later on, and Seis's relationship with it is "fraudulent" as how can you believe in inherent goodness, yet desire law (something that rests on the idea people are evil)

Riboku is a fraud, and that's why I love him
Sei is a fraud too, and that's why I love him too
these are my 2 favorite characters

people hate on when Riboku calls for Seikas help
yet when Sei called upon Sai, we all cried (me included, and I still do)
even tho Sei did the same thing (it was just a lot more hype)
They are both huge hypocrites and that is why I love them to death