First, of all harem (bar Kanzashi, who haven't show up, and Laura who is paired with Charles) she is the only one that has no past ties whatsoever to Ichika.
Second, the focus all been put on everyone BUT her in chapter 11. In fact, someone in TvTropes pointed her demotion as hilarious (I'm not really happy, but I knew it's truth).
Third, Kanzashi at least has clear reason to fell for him, but Cecilia, while understandable, is not interesting enough to develop.
I'm currently struck with this, because in my plan so far, turning point of Cecilia's role is after the Madoka Kidnapping where Cecilia serves as her good counterpart. And that's about a dozen of chapter ahead (yes, I plan a lot and write too little
). I need something I can apply now, or few chapter ahead.