Methods for re-releasing rare skins. (Champion Mastery idea)

Here's an idea Riot should consider when re-releasing rare skins like Championship Riven. The main problem with re-releasing skins like these is that it gives EVERYONE an chance to grab them therefore reducing their value and rarity. I've the idea that they should link the ability to purchase skins of this caliber to CHAMPION MASTERY LVL. Like, if Championship Riven was ever re-released, make it only available to people with either lvl 5 mastery on her or X amount of champion points on her. This makes it so only people that already play her can get the skin and people that would just be buying the skin because it is rare wouldn't be able to get one. it'll also prevent people from making smurfs then buying the skin on the smurf then selling the smurf later on for profit. I have another idea that every like 100K-150K mastery points someone gets on someone, they get a mystery skin for that champion. This will allow loyal but poor players to get skins on their mains and enjoy the game more. It'll also encourage people to play the game more, so they'll get more points to get those mystery skins. Riot, I hope you see this post and maybe consider the ideas presented.