I'm actually satisfied with the amount of story uncovered regarding Genkaku. We learned of his history, starting at when he was part of the City-State right through to his death. Maybe if the time setting is right, in an upcoming Genso Suikoden game, or even a gaiden, we could learn of Genkaku and Han's childhood, but I think it's safe to leave well enough alone for now.
A good assumption, dragonmasterx. It's true the Hero does/would resemble Genkaku in his younger days. Also, he could have indeed passed his rod down to Nanami. That would explain the similarities between Hero V's 3-piece rod and Nanami's rod.