HI Riot, here is an idea

How exactly would a piece of metal shaped to open a lock be forged into a metal box with a Hextech locking mechanism containing something you didn't already own?

In all seriousness, though, while I wouldn't mind some way to get boxes more often than once per S-rank per champion per season, this idea doesn't seem like the best way to go about it, especially not with all those players complaining of having many more boxes than they have keys.