Hitler and Stalin had modern technology, communication and organisation at their side. Unlike Rome however they lost and we do not have to listen to their mythology.
They were innovators and though their crimes were not new they were on a scale unheard of before their time.
Rome was similar. Everything they did was known before the romans came but they killed and enslaved on a scale and efficiency never heard of before. They were innovators too.
They also enforced peace over the Mediterranean World for four centuries, with occasional failures, but far more peace and prosperity than had been known in the previous centuries of the Hellenistic Age. Yes, the Romans were ruthless, and sometimes brutal, but so were their rivals and enemies. The Romans brought a rule of law and if they were slavers, they were also civilizers. You can't readily divide up the good and the bad because they were all tangled together.
Napoleon, likewise, has little in common with Hitler or Stalin, or Pol Pot, or Mao, or their ilk. Neither the Romans nor Napoleon made the error of thinking they could rewrite human nature, Hitler, Stalin, Pol Pot, etc. tried to do exactly that.
(Napoleon actually brought an end to that kind of thinking in the French Revolution.)
