Don't the items glow most of the time? They don't glow in mini-games (where she locks you in a room and chases you after a few seconds) though IIRC, so I agree with you on that.
About Saiko chan's body, I worry if they become any bigger, they are just going to get "unnatural looking and bloated" like is the case with many anime characters, especially in hentai (wait, it was research, research!). I prefer this size as they are big without feeling unnatural.
But I do think it would be nice to customize Saiko chan as that could add some replayability to the game. Or add other clothes for her, like a different school uniform or swimsuit or something, after escaping from her once to encourage replaying the game.