It's a double edged sword. I'm a new player, so I really like being able to get a couple of the awesome skins I missed by not joining sooner. At the same time, I fully empathize with players who had bought the skins on their original release and felt cool that no one else could get them. It's quite normal and common to feel cool for having something that someone else can't, so YES re-releasing them does reduce their value, but since it was a limited purchasing window, it is not reduced to zero. There are still many people who will marvel at your cool skin that they can't have. I do, however, see Crimson Akali about every third game now. She's very popular and now many many people have her, myself included.