I always thought that the deck building system and card drawing system should be different. Decks should contain finite number of cards and finite copies of each specific card. (5 copies of X card, 3 copies of Y card, etc.) With some min and max restrictions (e.g. min 5 commons, max 10 rares etc).
It would be more realistic and severely eliminate luck factor.
I'm not saying that this should be changed, it's just a thought. I know that this is no trivial thing. It would completely change the game. Also a lot of the current cards, mostly summoning/discarding cards, wouldn't work well with that model.