Tbh she is different to them in that she's been part of the party, circa Mazibuko's party leadership, for around 13 years now, before being as prominent as she is now? Still there despite the so-called "exodus".
Mazibuko became parly leader after being an MP for two years, with no prior political experience. Mmusi became party leader in 2015 after only joining in 2010.
And last but not least, it seems Gwarube has high rep. She was even part of the GNU negotiation team for DA alongside Gogo and Tony. She's been National Spokesperson and Chief Whip in Parly. My guy, she's a minister now.
So to dismiss her chances because she's "young and black" is stupid, and all too ANC.