Khan Noonien had all the classic elements of a villan, He was not the Shizon like hahahaa i have a big ship and i will blast you all to the stone age. He was some one you could relate to in his vengeance, though i would not go around killing people. Even McDowell in Generations was ok at least.
But i am worried Baba's Nero will join this growing list of failed villans. Anyway since the movie is about Kirk, Spock and gang most of the time it would not matter