Re industrialisation - perhaps some sort of POD that makes SA bigger (with S Rhodesia, SW Africa and Botswana) then maybe either generate a bigger industrial base from that fact alone, or create the political conditions for a large import substitution programme that forces mass industrialisation
Yeah, that's not a bad idea. But, remember South Africa is already pretty industrialised, by African and global standards.
Maybe, getting rid of the 2nd Boer War somehow, may lead to a more prosperous South Africa. No war will lead to less animosity between the Afrikaners and English Saffas, and perhaps lead to increased immigration. Immigrants will be likely to support the more forward thinking Jan Smuts and his South African Party, than the Nationalists. This may also lead to butterflies, leading to a qualified franchise perhaps.