I always found her to be the least attractive girl in the series, but as limited as her screen time is and with such stiff competition, it's hardly her fault.
@ dap00: I mean, you might not be wrong, but one thing she has out of all of the others is that she's the least problematic. And when the competition is your obscenely horny twin sisters-in-law and a teacher who WILL get fired if it's found out she has the hots for a student, being the least problematic has merit by default.