Thanks, you all confirmed some of my thoughts. Hamson is playing her best all season and it seems like it's because Robbins-Hardy is putting them high enough to hit over the block, same with Gray. Willardson-Godfrey sets the middles better, but Hamson and Gray's play is why they're still playing.
The point that she's a better passer makes sense too.
My only other thought was that Willardson got hurt in the Arizona game when she and Young dove in to each other for a ball. Whatever the reason, I'm glad it's working!