I think this would be nuts. It would have people holding big gold cards in their champion level decks, and every so often someone could catch the chance to win a bunch of reward cards, not every day, but whenever they are lucky enough to get their number drawn or however it's decided. On the lower levels too it would encourage even more play if it's based on total number of games played at each level by everybody. The nice thing too is that it wouldn't force anyone to do anything, again, a purely upside move out of the player whether they would care take part or not.