She was a tomboy while still being quite the girly-girl. Of course, Zoe was more "badass", but Kaylee's a special type of female hero that more actual women can relate to. Just because we get down and dirty with the boys doesn't mean a girl can't go to a party dressed like Lil'Bo Peep, thank you!! I mean, not that I would, but the general sentiment is what I'm going for here.

And Kaylee may have been a bit "ditsy" at times, but I wouldn't come near calling her stupid. Anyone who can keep Serenity in the air deserves some credit for intelligence