Its sad to see the old girls go, i like that instead of leaving one without the other they took both out at once.
I think a better option would be to see them turn there pride into a larger pride. It's a fantastic oportunity to keep marion and her daughters together, bring in some new lionesses like those from monarto. Then introduce new males, if they used billabongs males they would have a genetically valuable pride to work with, where breeding could be spread out and multiple females could be bread from. Mogo's large pride is a sight to see, it wuld be good to see western plains replicate this.
Lwazi and his sons could then be separated into a bachelor pride, in the other exhibit. Or moved to a private zoo thats after some lions for display. Bonus points, this would actually follow the dispersal pattern lions follow in the wild.
They built a large habitat for the lions, it would be nice to see them take the opportunity to create a large pride for the space they have.