Female champions have been gifted with great flexibility in regards to skins, being able to get skins that range anywhere from strong and powerful, such as Project Leona, to more cute and innocent, such as Star Guardian Soraka. Most of all however, they are given access to "sexy skins" skins that are made with the clear intention to have them appear sexually attractive and alluring, such as the new KD/A skins, and Officer Caitlyn.
All I ask is why can't male champions get skins that make them look sexy? Men have curves, too.
Take the Death Sworn skins for example. Death Sworn Katarina is a sexy specter with black skin tight pants that show off very valuable.. assets. Death Sworn Viktor and Zed however, are your more traditionally scary ghost/spirits, with Zed having a skull mask for a head. What if I wanted to see a sexy ghost dude?
A female friend of mine who also plays League says she feels, for lack of a better word, empowered when she's playing a female champion and using one of their more sexually attractive skins, with Battle Bunny Riven being her favorite. I think it's safe to assume that male players would like to feel like this as well when they're playing League.
While Rakan and Kayn are great additions, being male champions that are designed to be "pretty boys", League can always do better.