Shit that’s an almost Impossible question to answer for me.
I think that a people should ultimately be lead by a vision/idea/ideology/concept, not by a person, ideas are immortal but men and women live and die, they also can be corrupted or lose their way.
I think Black people, since our Emancipation and later decolonization of African and the African Diaspora should be lead by one idea: Pan-Africaonism. The men and women who lead us need to embody the idea, vision, protocols, and policies of Pan-Africism and lead us to Global Pan-Africanism, any leader who departs from or who fails to embrace Pan-Africaism is unfit to lead any Black people or organization.
If I had to pick a leader for the African Diaspora I’d pick Haiti, the whole nation; Haiti should be the the African Diasporic Capital, and every African of the Diaspora needs to take on and fulfill the mission of the Haitian Revolution as we restore Haiti to its proper stations among nations in the Western Hemisphere. We should turn to Haiti like Muslims turn toward Mecca to inspire us, and unite us.
If I was forced to give greatest leader in history in the form of an individual that would be Yaa Asantewaa, she brought hell the the British Colonialist when many other nations were simply bowing, he name alone inspired once broken men into battle. She lead the last of the Ashanti Wars and planted the seed for anti-Colonial Resistance that is germinating today.
There are other great leaders in academia, science, state-craft, Revolutionary Arts and Culture, etc.; you’d have which are all valued and have their own requirements for leadership, that’s why it’s hard to say who’s the greatest, because what make you a great warrior could hamper you from being a great Statesman, or Artist. We need em all to Liberate ourselves and unite all Africans.
So I’ll run with Yall Asantewaa, but that’s stricly an opinion; I’m others will have their own pick for greatest African Leader.