The poster who mentioned the different economic histories of African countries got it right. I see people lumping in all African countries as if they had common experiences outside of being colonies. Even if we compare Africa to other colonized continents you will find that the type of colonization was different.Many places in Africa were uninhabitable for Europeans and some of the colonial authorities struggled to increase the white population. The South American style of colonialism is maybe replicated in Cape Verde and nowhere else on the continent. The South Asian model , particularly the one used in India, was a favored model by the British with governors and chiefs helping in the administration of colonies. All of these differences are important because they affect or lead to the creation of the types of institutions that were inherited at Independence. The argument about institutions has been popularized by Acemoglu who contrasted the differences between North America and Latin America primarily on the basis of such differences. If we look at East Asia and parts of Southeast Asia which are really the post colonial societies that have managed to catch up to the West in terms of GDP per capita you will find that a lot of their policies were considered unorthodox, the World Bank had a voluminous report about their development strategy that proved to be controversial because they had policies that eschewed free markets such as protectionism, currency manipulation,IP theft, financial repression, "selecting winners and losers', and preferential access to foreign currency , loans to select companies.
African countries did not have a legacy of these large industrial type of corporations like Japan. Colonialism initially took place through charter companies like the BSAC and those were the people initially tasked with running the countries until the Governments took over. At independence the capitalist foundation was largely based on this exploitation, in Southern Africa as well as in places like Ivory Coast you had agricultural marketing boards set up for the express purpose of shielding white farmers from African competition by paying a premium on their produce and these later became a source of rent extraction by independent African governments. We also had stock markets in places like Rhodesia and SA for the express purpose of financing mineral extraction and in the event of failure to find minerals the charter companies turned to land theft. Land reform took place in East Asian countries because it was seen as a solution to rural poverty.In settler colonies those land ownership patterns reinforced that poverty and forced Africans who depended on agriculture into an exploitative wage economy. The pattern is obvious in countries with land problems such as Kenya,SA and Zimbabwe because of that history. Other countries like the Ivory coast had a land owning class at independence but the french gave the countries an option of either continuing to be economically linked to France or go on their own for independence and i think only one country chose full independence. What this meant for those countries was the dominance of French capital in their key sectors along with other merchants or traders from places like Lebanon.
In the case of leadership i think no one can deny that there have been some pretty bad leaders on the continent and they were either short sighted in preference for short term political gains or that they inherited countries that did not have much going for them. I look at a country like Botswana that is often cited as a success story and its inequality and income per capita is nowhere near what the East Asian countries achieved.Namibia with its diamonds and uranium is also well run but still has those problems and that is largely due to that inherited inequality. Countries are bound to have weak or incompetent administrations at some point in their history but i am not convinced that this fact alone can explain why we dont have a Japan and South Korea. Countries like Nigeria would have benefited without those military rulers but that does not mean they would have turned out to be Norway. They are far bigger and a more complex country to run compared to a small country like Norway, i would liken them on size alone to countries like Indonesia or Brazil and we have all seen how complicated those countries are to run.