Skin Buyback and/or Trading System

Am I the only person who has bought a skin for a champion early into their release, and a season or two later realized that they have two or three skins for that champion, and only one of them sees any use?

Something I would love to see is the ability to sell skins back. Not for the full value, of course. For a portion not exceeding half of their value and not less than a quarter. Or the ability to trade or gift them to our friends who don't have and may want them (with two step authentication or something of that nature for security and discourage hacking to abuse this system, of course).

I fully realize the scope of the undertaking a system of this nature would demand, so I don't expect it to be here Soon™. Just ask that it be looked at as a future option. Thanks, RIOT.