The ANC cannot recall Zuma without causing enormous insult to the Zulu nation. The Zulu nation within KZN province is currently a massive ANC voting bloc bulwark against further electoral decline, and the only reason that KZN ANC maintained its electoral dominance, remaining unchanged in the recent election, where each of the other 8 provinces saw an average 10% drop in support for the party, is due to the President of the ANC and country being 100% Zuluboy.
Additionally, were Zuma to be recalled, he would enact retribution against the ANC in the form of quietly agitating violence and unleashing mayhem. The ANC know this and Zuma knows this but nary a word can be spoken. Should this happen, and after the tumult, the ANC would hasten its demise as KZN returns to the IFP, with a DA IFP coalition running the country after the 2019 general elections. Damned if they do and damned if they dont.
The only small way out is to bring another Zulu into the presidency to replace Zuma, and the reason why some pundits are bringing up the name Zweli Mkize.