One man does not an army make. Most of the soldiers in Napoleon's army were pure blooded French. Plus, Corsica is a French territory, so that argument is invalid .
In addition to Waterloo, Trafalgar, and the Spanish campaign, Napoleon led the French army to one of the most catastrophic defeats in their history - leading half a million men into Russia kitted out for a summer campaign alone, and bringing home only 10,000, as depicted here:
Whatever his successes, his ambition ultimately led to his own destruction. (Like other emperors before him, his overconfidence was his weakness