Korra has a much smaller cast so far, being a shorter series with a smaller scope. The only prominent young female character are Korra and Asami, for the moment. Korra's twin cousins are joining in the next season, and hopefully other women as well. It's a bit of a sausage fest right now... You could also compare Pema and Lin, but they're in middle age, so I don't know how helpful a comparison that is.