It's not clear that she will ever become the passer Sarah is. But that's asking her to become one of the great passers in the game today. So, I'll cut her some slack on that one. Also, to appease
@Vowelguy, she doesn't finish at the rim as sure-handedly as Sarah, nor does she see the court quite as well -- judging from her passing mistakes. She doesn't appear to be quite the shot-blocker Sarah is, though this may be because she deters shooters.
What she does comparably well is pick pockets, and shoot 3s -- she's even doing that at a better clip right now. She runs the floor more quickly, though Sarah doesn't really need to be any quicker than she currently is given how well she uses her body against defenders. It's surprising how differently the two of them run in the transition game. Sarah never seems rushed and isn't concerned about outrunning smaller guards since she is confident she can score over them. But Blanca runs in a headlong sprint, as if she were racing herself down the floor. It's kinda thrilling to watch. Where Blanca's quickness advantage really shows up is in her half court drives to the rim. It looks like she can break down most defenders off the dribble. I think her perimeter accuracy plays a role in this, since this requires defenders to stay too close to her. The funny thing is that Allie -- who is nowhere near as quick as Blanca -- is able to snake her way to the rim as effectively as Blanca. Go figure.
As for the rebounding, Blanca doesn't seem to be as focused on position and boxing out as Sarah, and I'm not sure she has quite the strength in her hands that Sarah has. She can address the one perhaps more than the other.
One thing she is when she comes off the bench is explosive, which is quite a contrast to Sarah who is more like the rock that her teammates can rely on. The missed layups and bad passes get in the way of her playing a similarly steadying role to Sarah so far. This may change. But much as KK and Ash could change games when they came off the bench last season, Blanca can do that all by herself.