I always find it interesting when a contemporary argument boils down to old ones. (This isn't a criticism). Your argument against the Great Man Theory is best expressed in War and Peace, where Tolstoy goes on long discussions on the imaginary significance of great men, including obviously Napoleon. Or, as Isaiah Berlin says in the "Hedgehog and the Fox: An Essay on Tolstoy's View of History," Tolstoy perceived a "central tragedy" of human life:
...if only men would learn how little the cleverest and most gifted among them can control, how little they can know of all the multitude of factors the orderly movement of which is the history of the world...
...if only men would learn how little the cleverest and most gifted among them can control, how little they can know of all the multitude of factors the orderly movement of which is the history of the world...