I can see where you're coming from.
My feelings have been FY is a series that Watase started writing in the 90's so there is a lot more to interconnect compared to their other works, which have mostly been stand-alone fantasies or slice-of-life. I think besides FY, only Atara and Ceres have similar scales to the cast of characters, location, and lore.
Genbu and Byakko have this added pressure as the precursor to the original, having to tell a story that doesn't disrupt the groundwork of the original but still offers something new for older fans to be intrigued by. To me, Genbu and Byakko is Watase's chance to go back and flesh out the world-building, because as much as I enjoy the original it does come off as melodramatic being motivated by romantic tension over external issues that the priestess is summoned to resolve. I am sure Watase is aware of this criticism and is developing the world so the stories don't feel like they are being dragged around by the romantic problems between teenagers.
I think Watase is good at adapting to how audiences' tastes are changing and is showing their growth as a writer since they started.
--sorry for the long reply, most people I know haven't read much or any of Watase's work and I got excited to talk about it.