Well, the plan to use Hextech Crafting for Champion Mastery was in discussion all the way back in April in the PBE boards. The exact process had not been defined at that time, but you can track their discussion about their plans. Surrender @ 20 had a fairly detailed article at the start of last patch concerning this subject, since it was being introduced without any "readily free" means to advance. The gist of the discussion is that they might make champion shards available through the store for RP and IP. They are still undecided how they want to go about this, as they were throwing around ideas of buying champion shard bundles for like Demacia as well as simply having it be a random generator like the Mystery Chests.
It's one of those patience is a virtue things. Since I was aware of the possibility of them using Hextech for mastery, I've been hoarding my champion shards. Originally they were talking about rerolling three champion shards into a Level 6 Champion mastery of your choice. Obviously that did not happen, but as I had those shards available, it was a small task to disenchant two for the 500 essence I needed to upgrade my Leona to a Colossus. While I don't have enough shards to upgrade all my Level 5 champs, I don't think it will be too long before they implement some form of easy access to champion shards. Give it a month. Maybe two.
