I think I can make a better argument as to why TAR won't be going near South Africa for a leg this time, and avoid Jo'Burg except as a possible connection point elsewhere.
During this past decade TAR hasn't gone to a country that was holding the Olympics or the World Cup until a later season was filmed afterwards,
Examples:
Sydney (2000 Summer Olympics) TAR 2
Salt Lake (2002 Winter Olympics) TAR 8
Athens (2004 Summer Olympics) TAR 9
Torino (2006 Winter Olympics) TAR 12
Beijing (2008 Summer Games) TAR 14
World Cup (2002) Korea TAR 4
World Cup (2006) Germany TAR 14
There's no question Bert loves taking the Race through Olympic venues; he's plotted it that way enough times; and so far he's batted 1.000 in doing so within a year or two after the event. But he's been very consistent in avoiding those places in the run up to and during those events.
So I think the tendencies are that South Africa and Vancouver will show up in the next year or two; I just don't think the odds are that good for South Africa right now, although Vancouver sould be a wild card towards the end of this race currently being filmed.
I also think that for various reasons, much of east Asia is not as likely this time. Thailand is definitely off the boards until things settle down politically there. India has had problems in the past two years; and the show has been to China twice and Japan twice in recent seasons. Malaysia abd Singapore was visited this past season. Indonesia is a possibility, but the show has avoided there because of the potential for violence. (And you can't go by what the US State Department says. TAR has long relied on its own Security resources to help TPTB decide where to go in relative safety. Which leads me to this - I think the possibility are good for Australia and New Zealand this time around, and perhaps even an eastward route across the south Pacific to South America before the finish line somewhere in the southen or eastern U.S. TPTB have never done it that way, (and they hadn't gone westward across the south Pacific until a few seasons ago) and I think the odds are better for that this time given how quickly they got out of Europe to Africa.
Just my $,02. YMMV.