Free Champion Skin Rotation?

Well, I was recently thinking of how bored I got with just default skins. Note** I don't buy RP very often - once in every 4 months or so. I thought it would be cool if riot included a skin for maybe 3-4 champions, so everyone would see whether its a good skin or not. Not saying that all skins are bad, but personal preference. This way, we are able to see the skins Riot makes :) Just my thought. Pls no hate :(