You are correct.
The limited over cricket contests (20/20) are won or lost in the first 5-7 overs in my view.
The fielding side is restricted and the new ball allows runs to be made with this restriction if the batsman have the talent to score instead of building up the bowling stats for the fielding side.
Some of the Indian, English and Aussie batsman have taken advantage in the opening overs to make a good start but alas the RSA teams mostly appear to struggle.
Exceptions have been Quinton for example but no other opener has shown the skill/talent to make a great start, more failures from good batsmen has been the case.
Sure Quinton has blown many an innings by going after the bowlers but most other openers have failed dismally at opening an innings.
Brevis is very talented but he has never had the chance to show us, perhaps it is worth a shot.
But we need to score at the start of an innings and set a scoring pattern/plan not at the tail.
Sadly, the Proteas have an absolutely dismal open batting record.