The failure of many African countries to marry Independence with Freedom is easy enough to explain.
Independence is an event: the colonial Power hands over symbols of authority, the new flag is run of the flagpole and the army salutes it, the police band play the new national anthem, and everybody has a marvellous party for the rest of the night. But it is a one-off, unrepeatable event.
Freedom is a quality of life, something that is never perfectly attained. You have to work constantly to achieve freedom and to defend the freedoms you have achieved, because there are always threats which could reverse all our gains. Independence demands one kind of leadership, good at organising masses of people for a single limited aim. Freedom requires the ability to fight an undending struggle towards an end whose form will vary with time; multiple small struggles, involving large numbers of people slowly learning to exercise their political muscles, with a leadership that knows how to encorage every initiative of the people, but can keep an eye fixed on the longterm strategic objective. That might require a “philosopher king” straight out of the pages of Plato, but Plato never produced a philosopher king in the flesh. His disciple Aristotle may have tutored Alexander of Macedonia, but not much of the tutor's philosophy seems to have rubbed off on to the grat conqueror.
Still, Africa has produced at least one ruler who had a philosophy, lived it and instilled some of it in the thinking of his people: Julius Nyerere. Thomas Sankara in Burkina Faso could have been another, but the CIA prevented that by having him assassinated after a two-year rule in which he had raised the country's literacy rate from 2% to 20%. Might the Congo's Lumumba have proved himself another leader with vision? His statement of his vision at independence probably sealed his fate, so we can't say how far he might have implemented it if he had lived. Kwame Nkrumah in Ghana wrote books that still inspire some. Didier Ratsiraka, who took power in Madagascar in a coup in 1979, had a programme for reform; I don't know how successful he was. The South African Peoples Charter was not produced by one man, or by the ANC alone, but a congress more representative of all the people than anything else that country has seen,and the Charter stands as a vision statement by which any South African government must expect to be judged. Can any other continent in any century claim more than this? Inspired leaders and inspired movements are rare anywhere.