I don't have any real insight into this, but recall that when the independent review into Heraf's appointment/sacking was completed, it noted that only about half of the Ferns participated in it, and others chose not to (and again, this is my recollection, I haven't bothered looking it up again).
I remember that raising a few eyebrows at the time, and there were suggestions floating around that not all Ferns thought that Heraf was the worst human being ever.
Even if it is the worst case scenario, a player power/culture issue that requires addressing, if its a trade-off between Erceg and Heraf, Erceg wins every time. One of the world's best defenders vs a coach that couldn't tailor his approach to the women's game, or the NZ psyche. No brainer.