Don't really understand why the reviewer didn't get why the Mezarte kingdom wanted the power of the Iroph. It's patently clear they wanted to their royalty to breed with them so they had heirs to the throne which were pretty much immortal. Also it was clearly explained that the cloth they weaved held their history and was used to communicate with each other. Outside their clan it was also a highly sought cloth. Also it's plainly obvious why the Mezarte military would capture the Renato to use in battle.
Unlike other directors, Okada didn't over explain the world she created to the audience. The melodrama should have been reined in. It spoiled the film for me. But the focus on motherhood was really interesting. Considering her childhood, it's no wonder Okada has explored this theme in her work numerous times.