I feel like Riot's skin team isn't on the same page as champion design.
It's never been a secret that Officer Caitlyn is supposed to be a "stripper-dressed-as-a-cop" rather than an actual police officer. It's acceptable because the skin was made when Riot was still in their "teenage" years, and Caitlyn is a pretty sexualized character anyways.
Then the champion designers goes and creates Vi: A tomboy that isn't afraid to show that she is female (ex. pink hair), but is definitely not eyecandy.
http://img2.wikia.nocookie.net/__cb20121212052715/leagueoflegends/images/a/a0/Vi_OriginalSkin.jpg
Then the skin team gives her a skin of the same theme. I'm personally not a fan of it because it doesn't fit the character, but I can look the other way considering it's a "matching skin" (since she and Caitlyn are partners) and it was released as kind of a halloween costume. The also only made her sexualized because it was part of the skin theme.
http://img3.wikia.nocookie.net/__cb20141116061957/leagueoflegends/images/2/20/Vi_OfficerSkin.jpg
And then they make these in the same skin serie:
http://3.bp.blogspot.com/-Y0IaO5dv_KY/VGrjohKzaVI/AAAAAAAAdik/wo1Y4LZC5a4/s1600/Trundle_Splash_4.jpg
Oh look, now there's a troll and a bear who are easier to take seriously than the two people who are actual police officers lore-wise.
Other skin-themes have the same problem. The medical skins for the ninjas for example (although those skins are older, but still).
I feel like while the rest of Riot's design team are growing up, the skin team is still locked up inside it's mom's basement.