Maybe emo is too strong, but the Ravenclaws we know a fair bit about are certainly NOT a logical bunch.

Cho Chang is a bit of a weepy mess. Michael Corner gets into a sulky snit over the results of a Quidditch match and breaks up with Ginny. The Gray Lady turns out to be a spoiled sulky brat who decides to spend the rest of her nonlife drifting around Hogwarts feeling not doing much. And Luna, though not emo, definitely operates on something of a different plane than everyone else and relies a great deal on particular beliefs and intuition and not necessarily logic.