I find that many post-liberation governments in Southern Africa are less concerned about creating wealth and more concerned with sharing wealth. The difference is, you can share more wealth once more capital is created.
That being said, land reform is a serious issue - but what would the EFF do to avoid a degradation in production while distributing land to poor people. Farming is hard. What inputs would an EFF government provide? How would land reform take place?
On Import Substitution - you're economic history is wrong. IS has been tried in many African countries because the nationalist/socialist governments which took over these countries in the 60s and 70s thought it was the best way to industrialize. Of course, they were wrong creating debt-crises which ballooned by the early 1980s. It would be very sad to see South Africa gone down a path already tread by Tanzania, Nigeria and others.
Read this:
Industrialization in Sub-Saharan Africa and import substitution policy
Export-led industrialization is the way. That's why Mexico (which did IS for decades) only started to develop when it switched its industrialization strategy in the early 1990s to export-led development (plus NAFTA).