He's not going back down in weight at this point in his career. He said he wants to move up to Featherweight by the end of the year but give his body time to fill out and defend his belts at Super Bantam first. Realistically the only guys left at Super Bantam are Goodman, MJ and maybe Picasso who's still very young and lacking in signature wins. Maybe eventually Junto Nakatani can move up and do a superfight in Japan vs Noaya before Naoya retires.
At Featherweight guys like Figueroa or Rafael Espinosa are good fights. I think Featherweight is as far as Inoue goes, Inoue does not have a frame to fill out and while he's fast and powerful the more he moves up, the less power he's got. If Inoue unifies FW he's gonna go down as a GOAT.