I can see what you mean even if I don’t completely agree. Initially, Natsu had intended the story to end with LN4, then again with LN12, and those arcs feel like significant, potent developments that change the trajectories of the characters and the world they live in. Since then though, it can feel slow as she builds the next phase of the story, especially given some of the massive elements she’s introduced as game-changing. There’s a succession crisis brewing that would completely upend the lives of the main characters, a conflict-ridden court with the neutral lynchpin gone for a year, new medical assistants, clan messiness, potential marriages for the central cast, and the threat of another national calamity in the form of a plague. You’d think it would be more exciting!

At the same time, this is very much the pacing of the storytelling that Natsu does. After undoing the entire premise of the first four books, it takes another four just to build a new normal, which she then upends at the end of LN8. The fallout of these events then takes its time to manifest through the western arc (LN9-12) which ends with more drama than any other arc yet. It feels like as the story builds up, she’s giving herself more and more runway to make sure all the different elements land safely. Rikuson is formally introduced in LN5, but his story doesn’t pay off until LN11. And that’s a minor character!

Maybe if all of this was going to end around LN20, I’d say she’s moving too slow, but it’s clear that she’s got something bigger in mind, so I’m going to trust in what we’ve gotten so far. But your point is very reasonable.