Well this is a conundrum would the wisest shinobi be inferred as the smartest shinobi, or as the one with the most knowledge??? Lord hiruzen? Or GOD tachi? For let us not forget without our mentors we would be nothing...I think. So brothers and sisters let us ask ourselfs what is wisdom? It is not whether we have knowledge or not, but how we choose use it's power, for the matter of selfish desire or for the righteous nobility or our brothers and sisters. Because think about it even lord itachi himself stated perhaps his younger sibling was the change he was waiting for...