It's obviously far too late for this, but these last few chapters made me realize the series should have pivoted to Hitomi being the protagonist. I actually enjoyed these chapters. It felt like a
story where there are
characters who want to do
things for
reasons, and Hitomi is the engine whose meddlesome nature keeps it all in motion.
the fall off needs to be studied
I don't want to reread this whole-ass thing to figure it out, but I think the core issue has been the change in concept. I'll break it out like this:
Phase I: Everyone loves Komi purely because of her aura; not who she is. Komi is frightened and alienated by this. Tadano is level-headed enough to notice this. Silly, one-dimensional characters hoist their expectations on Komi, but now Tadano is able to intercede and allow these characters to actually see each other as individuals. This creates depth.
Phase II: This character depth allows for more complex plots and relationships between characters. Now there can be actual drama that the audience feels invested in.
Phase III: Everybody loves Komi because of who she is, and she is seemingly able to solve every issue because of this. Tadano and her now drift aimlessly through the sea of indistinguishable side-characters and their pointless problems we have no reason to care about.