My one problem with Hextech Crafting

Riot I love hextech crafting a lot. I think it was a good step in the right direction. However, what bothers me is that a player can get a champion\skin\ward skin they already own. With a skin, it's alright because you can reroll 3 of them into something that is permanent, but with champions all you can do is activate it, upgrade it, or disenchant it. If you already own the champion you get, disenchanting it feels really lackluster and not special at all. I think a similar system with the skins where you could re-roll, say 3 champion shards for a new thing completely.