Guandao
Rajah of Minyue and Langkasuka
Why? He did much that was admirable. Supporting White Australia back then but giving Aborigines more rights was definitely a step ahead in his time. FDR never gave the Japanese-Americans he corralled into camps more rights. And many leaders like Lincoln who are revered nevertheless held questionable views on race (in Lincoln's case, on Native Americans). We were less enlightened back then.
He certainly was a dictator in some senses, but he was a huge advocate of multilateralism and brought Ethiopia to the modern world's stage in a major way and created Ethiopia's constitution. He also saw reform as necessary but knew of its potential downsides and guarded against this. As for the loss of power, I don't see that as a strike against him, just as I don't with with Pedro II. He also spoke movingly before the League of Nations in Amharic when Ethiopia was being invaded by Benito Mussolini, and pointed out some European nations' hypocrisy in being Ethiopia's allies but trying to appease Italy (caused some scandal in the day). The speech made Haile an anti-fascist icon, which color he share somewhat with Curtin.
I must confess I don't know too much about John Curtin's and Selassie's policies. I've read a book about scientific racism in Australia once. During Curtin's time, the Aborigines were viewed as a dying "race". Giving them more rights is nice, though the government probably had this expectation of them becoming extinct. You might as well treat the last survivors fairly. Looking at the wiki page for Haile Selassie, it says some human rights group criticized his regime as autocratic and iliberal. It also mentions the ethnic cleansing of the Harari. If he had actually made Ethiopia into a democracy or a constitutional monarchy, I would have more respect for him, but it seems like he held onto power for as long as possible. Ethiopia today still isn't an actual democracy.
I'm wary of more 20th century leaders. Just because it's the most well documented period of human history doesn't mean it should be well represented in leaders in the game. We'll get demands for leaders like Mao Zedong (Civ veteran....), Stalin (another Civ veteran....), Pol Pot, Idi Amin and Hitler.