Before modification by darius_sedai at 03/01/2016 09:46:30 PM
I suppose Cadsuane might have played a role in revealing the plot to the Amyrlin, even if she had no proof of the Black sister's involvement. Actually, it might have been the deaths of the Black leaders that allowed them to escape her investigation and saved the BA from being rooted out.
The pogrom opened the Black up to exposure given how wide spread it appears to have been. The Companion gives us more insight into the numbers of men killed, possibly in the 10s of thousands, and was a totally reckless move for a secret organization such as the Black. The last straw in Cadsuane losing the trail was likely due to the death of Sieren Vayu at the hands of the Red not long after Ishamael killed the Balck Ajah Leadership and placed Alviarin in charge. She seems to have gone to great lengths to shut down any exposure to the Black.