A massive injection of capital to educate the masses, trade schools established in all areas, the eradication of shamanistic practices like raping a baby to cure oneself of HIV or ritual murder in order to garner body parts for muti (magical medicine), and the establishment of small, locally owned businesses.
Mandela should have nationalized gold and diamonds for 20 years, then should have used the money to put electricity and water into the townships, thereby alleviating much of the hardship. He should also have built housing to replace the shanties. Plus he should have started trade schools, invested in creating an artistic culture, etc. He didn't.
It would take about three generations to right itself. Also, there are some things that cannot be corrected - only alleviated by education. The average IQ in Sub-Saharan Africa is 77, which means there are a lot of people with lower IQs.
Had South Africa not had apartheid, I think a stable middle class would have developed. However, there were other points - the Afrikaners were mocked and belittled in the country, and they were the majority of people. They were veey, very poor, probably equivalent to American rednecks. They were the ones that voted apartheid in.
I don't believe South Africa will survive, nor will it ever return to its first world status (until the 60s). It will get poorer and poorer, and eventually it will have a dictator like Mugabe. I think South Africa will go the same way as Rhodesia.