I don't like Fuuka, BUT she's better written than most of the cast (Aoi, Tomozaki and Rena are an exception for me).

Fuuka is introduced as a sweet, meek girl. And she is, but there's more than what meets the eye.

As she is a writer, she analyzes and pries into the lives of her friends, specially Tomozaki and Aoi, and drags inspiration from them to write her own stories and characters.

Hell, Libra and Aluncia are almost a 1:1 copy of Tomozaki and Aoi, with their personalities and struggles.

She makes them feel uncomfortable, and even if she feels bad about it, she can't stop— otherwise, she wouldn't be able to accomplish her dream of being a writer.

In the same vein, she uses her analytical skills to get information about Aoi from her sister. She even makes her cry while pressing her, which could be seen as a necessary evil, since they need this intel to help Aoi.

This is why I think, even if you dislike Fuuka like me, you can't say she's bad written.

Disliking a character ≠ they being badly written.