I dare to say from the story that we were getting that original WF didn't work out because of people like Sienna and Adam..

It would be slow repair And dunno if successful overall but not when you have Adam raiding some SDC facility in Atlas in the first appearance in his trailer ( And it was when Ghira was still a leader )..

Ghira could manifest all he wants but if at the same time Faunus was taking action against SDC, for example, it was all pointless.

Not to mention that it was probably Sienna that has convinced WF and other Faunus that her way of dealing with things ( Faster results ) is much better than Ghira which resulted in him stepping down.