A contraty to most posters I've found last chapter as a very interesting one. Now I'm almost sure, my
predictions about plot of this manga was right.
Most of us, me included, dislike Mary Sue types of characters, and we were disappointed when Medaka shown her superhuman abilities. No one expected humans with supernatural powers in this manga. As I've posted before - readers tends to dislike plot devices they didn't expected. But try to look at Medaka Box as a supernatural type manga - like Rosario to Vampire, Sekirei, Melancholy of Suzumiya Haruhi etc. Re-read this series expecting Medaka to be something supernatural (alien, genetic engineered human, halfdemon etc.), and to see another supernatural characters (IMHO we will soon see Shiranui as one).
Till chapter 17 I was unable do comprehend why author is showing Medaka as such kind of character. She looked too me like typical Mary Sue archetype. Now I know her motivation, and I could explain each of her strange actions and behaviours.
She is extremely insecure. She feel she need to prove her worth again and again. She wants to be loved and praised by everyone, cause she feel unworthy.
She is connected to Zenkichi probably because he was a first person, who loved her. He was Medaka "safe bay", she always could go back to him, he is a prof, that she is worth something - because there is at least one person who loves her. Because she has a lots of followers now, his importance is dimnishing.
IMHO Zenkichi role was also dimnished because author wanted to show us, how much he doesn't fit into Students Council. There were lots of hints that he himself or other people (including Medaka) see him as unfitting for SC (Medaka folowers). Soon, IMHO in next 2-3 chapters, Zenkichi will leave SC. IMHO this will be the moment, when real plot, and characters development, will start.
BTW - in Medakaverse there are 3 kinds of people:
superhumans - like Medaka, enforcer kid, and probably Shiranui;
geniuses - those with schoolarship - most of shown characters;
common people - Zenkichi so far was only ordinary human shown in this series for more than 1 chapter.