Rusty Blitzcrank Achievement System

What if there was an achievent for some old retired skins to be earned? Take Rusty Blitzcrank for example, the achievemt could be to own all of the other Blitzcrank skins, and then after you own them all, Riot could send you a notification about getting Rusty Blitzcrank and you would receive it as a gift. I think that this is an interesting idea and could easily be implemented into the game. Send me your thoughts in the comments.