Personally, I think that we'll see how effective Card. Mueller was in holding back the floodwaters of Pope Francis' agenda.
I wonder who Pope Francis will nominate in his place. It will be very telling as Card. Mueller speculative theological opinions were an issue with the SSPX and he was forced to affirm the faith because of their protests.
As Card. Mueller was one voice opposing a no-compromise canonical regularization, I wonder what is next.