A few years ago someone proposed the theory that every online forum thread (if it went on long enough) would eventually include a reference to Hitler or the Nazi party..
History never quite repeats itself, but it often comes close enough to sound alarm bells. Politics in the thirties was dominated by big public gatherings, in countries where the media was often either wholly controlled or wholly intimidated. Politicians in many countries could lie and be widely believed. Today it is very much harder to conceal the truth and very much harder to whip up crowds into angry mobs.
That Duterte was elected speaks volumes about the sad state the Phillippine people find themselves in, and the abject failure of past governments.
Germany also was badly failed by it's leaders in the decades prior to Hitler's rise, and one cannot dismiss the similarity, but at least there is little risk of Duterte embarking on serious military adventures in other countries.
If he remains in office for any length of time though, he may feel the need for new scapegoats. The muslims of that country should be fearful of that..
The problem with notions that history repeats itself - or nearly does - is that is is totally impossible to recreate the conditions around which a particular dictator rises to power.
I think it is probably true - very generally speaking - that dictators like Hitler, Pol Pot, Stalin, Mao etc. came to power as a result of political vacuums that someone was eventually going to fill. The Germany of the time of Hitler's rise to power was a defeated nation subjected by the Allied Powers to crippling economic reparations. There was overriding poverty, mass unemployment, a very real fear of communism, hyper inflation etc. etc. Rather like Trump in the USA today promises to cure every single one of America's woes - inner city poverty, healthcare, international disputes, eliminating ISIS etc. - without any real, concrete programmes for doing so, Hitler promised to lead the country back to greatness on the basis of ideas allied to fear, hate and suppression. On that occasion, Hitler won power. We will soon know if Trump does. (And if so, God help the world!)
Pol Pot's rise was first a result of the fight against French colonialism and thereafter of the disastrous American undeclared war on his blighted country. If the Americans, for whom colonialism after World War II was anathema, had just used its very considerable influence to get the French out of Indo-China, how different this region's history would have been. But America needed the French to bolster Europe against communism. Like many revolutionaries, Pol Pot gained much of his Marxist-Leninist ideology when studying in Paris. Stalin would never have existed had Nicholas II not turned out to be such a desperately weak, impressionable individual and then had not Lenin died at a highly appropriate moment (poisoned by Stalin as some have suggested?) Mao led a faction in a country that was barely holding together after the fall of an archaic millennia-old system of central authority.
So I think there is zero similarity between these and other dictators and Duterte. There is something in the Filipino psyche, perhaps a manyana effect left over from its period as a Spanish colony or even the notion that democracy will cure all, a result of its American colonisation, that leads them as a people to pay little attention to the past. Or are they almost anaesthetised to the corruption that ensures 90+% are doomed to live in abject poverty and rather naively believe that a popular leader, no matter what his policies, will gain them a few more pesos? It is certainly a country that has been extremely badly served by its elected leadership.
Getting back to the OP, South Korea's first female President, daughter of the military dictator who was assassinated in 1979 by the Head of the Korean CIA, has now been impeached and the action confirmed by the country's Constitutional Court. So the unbelievably stupid Ms. Park becomes open to criminal prosecution. Like most of her democratically-elected predecessors, it is a near certainty that she will be found guilty of corruption and jailed - but then pardoned and released after a reasonable period of time. Such is the nature of South Korean democracy.
There now follows a Presidential election in 60 days. The former head of the UN Ban Ki Moon was initially said to be in the race, but he pulled out at the start of the year. The most likely candidate is now the more liberal Moon Jae-in of the opposition Democratic Party, a politician assumed from his past views to be more in favour of some form of developing rapprochement with the North. He has also expressed the view that the US THAAD missile defence system should not be installed in South Korea. One wonders how Trump will react if he wins the election.