Like the way its structured to start with is the extremely tight view that drives home that all these other characters have their own lives and existence but you only ever the few bits when Frieren's around and then they're gone, while the pacing keeps up this constant feeling of time slipping inexorably away and being lost forever. It hits hard and is structured perfectly for those themes.

Then it hits a point where the story shatters into a bunch of separate threads and grinds to a complete halt in the way that stories that split into a bunch of threads inevitably do. It loses the tight focus and the feeling of "yes, these characters have their own existence but you only interact that during the moments you're actually there" sort of thing in favor of just showing you a blow by blow of everything that's going on with them, and instead of time slipping away no matter how hard you hold onto it it instead stands completely still.

It stops being unique and impactful and starts being "that annoying thing from BNHA where they spend like half an entire season going into excruciating detail about some little training exercise with mild competitive elements that every single member of a huge cast is participating in" instead.