nah, our big banks are perfectly safe. They are very well capitalised and ahead of Basil 3 requirements that only kick in during 2019. African Bank got reckless, especially with regards new loans and provisions for those loans. The biggies (and I include Capitec) have been slowly turning off the taps on new loans and we can see it in their bad debt ratios that are still very low. That said bad debts will be creeping higher but we're still a long way from the levels we saw in 2007 in large part because of new legislation.
That all said it will hurt earnings and while the big 4 are cheap I own none of them preferring Capitec.