Charlotte from the get-go suffered the "choice" problem.
It was either highschool rom-com or X-men clone.
When you try to do both it ends up badly, and you get this result.
You see the difference between Charlotte and something like Monogatari, is that Monogatari doesn't spend it's time in the highschool.
Ofc this show had nothing for me thanks to the highschool-over-plot setting, but at the same time, I'm surprised they even bothered to try at the end.
I still have no clue why the kids where the only powered. It seems utterly short-sighted, like the author made this just so it's only highschool setting.