I just realized I like Konami-senpai. She's a ditz and seemed unreliable until you meet her in the battlefield and you realized your lucky you have her on your team.
That goes for a lot of A rankers actually. Toma slacks a lot, Ikoma is an idiot, and Tachikawa has braindead moments (according to Q&As). But they're extremely reliable the moment you place them on the field.