Also - and this is my person opinion only - but without Hebikawa, this becomes an incredibly generic romcom school manga that we've seen plenty of times before. So I personally still read this entirely because her character exists; otherwise everyone else is pretty generic and formulaic in their presentation: Kusunoki is the "perfect heroine protagonist"; Keisuke is the ML who falls for the main heroine and attempts to get her to notice him by being generally helpful in all the standard ways; Otobe is the tomboy childhood friend who's over-protective, but then falls for the ML and becomes a Losing Heroine.
Hebikawa exists outside of that dynamic, and introduces depth to the arcs of Kusunoki and Keisuke that elevates this above the bog standard fair of schoolkid-age romcom titles.
100%, having a consequential past and it following him is very nice
Pretty sure you've (Think it was you) said it before, but Kusunoki acing all her tests didn't help her character, she became perfect when she tried, so her only fault is lack of effort
If she didn't ace them then maybe we'd see how she handles minor losses, or losses in general, does she ruminate, find ways to cope, or revert back to her awkward self, in my opinion would be cool
I don't like regressions, but reasonable triggers for them is great, also could serve as a point to show growth, show that she didn't fully regress (in the past she would) because she's learnt/grown to handle things better