I agree with the comments above. Given all their woes, I wouldn't expect SAA to be launching any new routes anytime soon.
That said. In the mid-2000's didn't SAA fly direct from ATL to CPT? I couldv'e sworn I was on a few of those flights. Though to be honest, whether it was the drinks from the lounge or onboard, or the hangover afterwards, there may have been a stop in JNB. I pulled a couple of old itineraries and it seems so...