Champion Ranks 6-7
How about instead of making us pay into the Hextech RNG system to get the chance to get Masteries 6-7, we make it so that getting ranks 6-7 gives you stuff in the Hextech Mastery system?
Rank 6: get 100,000 Mastery Points. Gets you a Champion shard of the champion. Rank 7: While Rank 6, win 7 games with an S- rank or better, one of which having to be an S+ game. Gets you a random Skin Shard of the champion.
Far from easily obtainable except for those who 'really' play a champion extensively, but that way Ranks 6-7 mean something.