Since Eve arrived a while back, she hasn't been a very good villain. We've seen her do evil things, but certainly not on the scale of Lucifer, and I had a hard time buying her hype, especially with a lot of tangential episodes along the way. Like the confusion which begun the season, there hasn't been a clear sense of where the season is going.
"Mommy Dearest" resolves this problem, getting rid of her character, and reintroducing Crowley/Castiel(?) as the main enemies. But it also brings up another question: why introduce Eve in the first place if she'd get ganked once they found her? There really seems to be little point to her other than providing a bridge to Crowley, and if that's the case, why was she made to the such a fearsome enemy?
What comes out of the episode is the information that Crowley harnessing souls to gain more power and Castiel is intimately involved with this. With three episodes left in the season, we'll see what happens soon enough.
Score: 8.6/10