Seems like these comments are split between people who are good thinkers and people who don't think at all. I don't think some of y'all realize that people don't change overnight. God forbid the author take time to develop the characters. Y'all know the manga isn't over yet, right? I mean, we're less than 15 chapters in. Have some patience.
As for Kurokawa, I'm loving her progress so far. She's clearly been a social outcast ever since she came to this school, and she was picked on constantly by the gyarus. Making one friend isn't going to clear away years of a built-up inferiority complex in a matter of days. However, the fact that she's been showing signs of opening up to Fujishiro, mainly wanting her to be the only person who calls her by her surname, is a welcome step in the right direction.
Also, I'm pretty sure we can all agree that Iro-chan is an audience surrogate, right?