Momiji was a lot more interesting near the start of the manga but many of her positive reliable traits were shared by Nayuta, and eventually Neko just wrote every moment that old Momiji would have had with Nayuta instead, leaving Momiji to only be the "crush on Mahiro" gag character. I agree that it's about high time that Neko revitalizes Momiji's reliable side and/or writes some new traits onto her in a focus chapter. His current direction for her on a greater level seems to be that he wants her to follow in Kaede's footsteps as a gyaru, so I think showing some legitimate development by having Momiji raise both her and Mahiro's girl power simultaneously on her own accord while lifting them both up would make for a great chapter.
