Cannot help but think think that Sisulu's campaign is designed to disrupt NDZ's campaign. The ANCWL and ANCYL have come out strongly calling for a woman as president and, through no democratic process, anointed NDZ. 

Sisulu has now made a move that will raise these issues and either force a democratic process to decide which way the respective leagues will go (unlikely) or that they get themselves distracted trying to discredit Sisulu in order to justify their support of NDZ. This will only isolate their supporter base further and advance the efforts of the real opponent, Ramaphosa. 

Personally I think it is a brilliant tactic by the Ramaphosa camp, as I do not believe that Sisulu is acting in isolation here. She might be arrogant but she is really smart too, and extremely politically astute.