South Africa did not choke against England, they were outplayed. It is as simple as that. A lack of preparation and game time contributed to the 22 run loss and the exit from the tournament. The Proteas did have a grueling season before their break, but 2 and a half months is a very long break. I am surprised that the team did not have a series against their neighbours Zimbabwe before hand to get some game time under their belt.
A warm up match against the Lions and the West Indies is far from proper preparations and it was clear in the bowling department. I don't think the answer is too change the side or fire the coach, but maybe relook the role some of the senior players play in the side.
Many feel AB de Villiers should take up the gloves permanently with Mark Boucher being phased out of ODI cricket and kept on as a test specialist, while Albie Morkel should be moved up the order, while a Ryan McLaren be looked at as potential all rounder. Faf du Plessis from the Titans should be looked at in a big way with Imran Taheer the leg spinner also considered for the Proteas mix. A new approach not a new coach should be used to lift the South Africans back to the summit of world cricket.