There are 5 African countries with a significant population (say >20 million) and a >= medium HDI. Those are: Algeria, Egypt, South Africa, Morocco and Ghana.
Of those 5, South Africa and Ghana are the least failed states, according to the index (before and after the Arabian spring). They actually score better than India and China, which both had a GP without too much controversy, so I don’t see how it can’t be done.
On top of that, South Africa has F1 pedigree. Unfortunately, the short and fast Kyalami (which would have been unique) is no more, because it had to make way for housing. The new Kyalami is still pretty interesting to drive on, but not really suitable for overtaking and in a very poor state, with no room for improvements.
Now, the South Africans could build a new track, it only costs as much as two World Cup stadiums, OR — and this option bears my preference — they could build new facilities around the Prince George Circuit in East London. The place has F1 history and a mighty impressive backdrop with the Indian Ocean. It’s short (3.9 km) and very fast, which would make it stand out immensely. The only problem is that I doubt the FIA would be happy with 40 second or less lap times.
Either way, I think South Africa should definitely get a Grand Prix in the near future. My only concern is that it will be either yet another sterile Tilkedome or yet another street circuit. Egypt could be suitable as well, but the country will need several years to stabilize and another couple of years to make plans and then another couple of years to put those plans into action.