SA should open with Cook - Richards
"He should bat at No. 3, where he is best."
He also has some advice for South Africa's decision-makers.
"If I was a selector, I would have selected Stephen Cook. He has had 10 years of producing some very good scores and been very consistent," he said.
Only one of the current selection panel was present to hear Richards' thoughts at the New Year's address after play on the third day but the message was clear. "You can't manufacture opening batsman," Richards said. "They either like it or they don't like it and if you don't like it, its very hard to be successful at it."
As an opening batsman himself, Richards would know. He would also be able to relate to why van Zyl felt compelled to try. "I can understand why Stiaan wants to bat there because there was no other place in the middle order," Richards said. "He wanted to get into the Test side and he was asked 'Will you open?' and he said yes because he has got a pretty good technique. But I think it has worked against him. I would have preferred a Stephen Cook."
Cook may yet be added to South Africa's squad, which will be announced at the conclusion of this Test match, for the next two Tests but, at 33, he would likely be a stop-gap, which has Richards worried about the country's depth. "Long-term I think the cupboard is a little bare," he said. "I don't watch a lot of franchise cricket so I'm not sure who is knocking on the door but if there is a young player out there, there is an opportunity for him."
In a time of transition in South Africa's Test squad, there have already been opportunities for bowlers - Kagiso Rabada is the most standout example but there is also Chris Morris, who made his debut at Newlands and Hardus Viljoen, who has been included in the squad. South Africa have a captain for each format and only Faf du Plessis really seems made for the job. AB de Villiers is over-burdened, sometimes with the gloves, sometimes with being the best batsman in the world - and prone to miscalculating the over rate - and Hashim Amla has been reluctant. In the last few weeks, he has been even more in the spotlight as results and his own rut got worse.
After a good start to captaincy in which he won a series in Sri Lanka, a one-off Test in Zimbabwe and a series at home against West Indies, scoring a hundred and a double-hundred in his first four matches, Amla hit a slump. His next 13 innings yielded only one half-century and his last nine saw him dismissed in single-figures five times. South Africa lost four out of five matches, including three in India.
Richards could sympathise with their fortunes in India and how they took their toll on Amla. "India had the best spinner on either side in Ashwin and he was always going to be the key. South Africa might not have prepared as well as they could have because I don't think they even thought the wickets were going to be exactly like that," he said. "Next time they go, they will be much more prepared about how you to go about it and the targets they set themselves as a team. Two hundred is a good target on wickets like that. Instead of playing the kind of cricket that Ben Stokes can play, you can't do it on those sort of wickets, you've got to plan differently and set your targets lower."
With the lofty goal of winning a first series in India in 15 years and keeping their unbeaten run on the road (South Africa had gone nine years without a series defeat away from home), it appeared as though Amla's anxieties over his ability to lead was bleeding into his batting and Richards noticed it. He also hoped for a return to better fortunes after Amla's century - which swelled to 201 - against England in the ongoing Test.
"He has to exclude what's swirling around in the captaincy stakes while he is batting," Richards said. "If he can do that, it's going to be enormous for South Africa. I don't think he is doing that at the moment. I think he worries about things that are happening from a captaincy point of view while he is batting and you can't do that. Maybe this is the corner he has turned."
Whatever the outcome of the Newlands Test, Amla remains "on a learning curve" as a captain, according to Richards and may still need to confront the question of "whether he wants the job".
"I'm not close enough to the team to know whether he goes in afterwards and seeks people out to see where he can improve or is he saying to himself, 'I don't know if I want this, it's affecting my batting'. And if we don't know those answers, we don't know how to plan for it. It is a decision Hashim will have to come up with himself. The most important thing for South Africa is for him to make runs, You can always get help in the field, you've got another ten guys around you but when you are out there batting, you've got to have your full focus on your batting."
Firdose Moonda is ESPNcricinfo's South Africa correspondent