I would love to see the ability of losing a card, for real and forever. I mean, it doesn't necessarily be one of our permanent and hard earned cards, but maybe a kind of brawl with some cheaper or easy reward that can be lost and win only in battles. Let's see you got some deck of 10 cheap disposable cards, but you get another that is golden legendary and also disposable one. You could sell that one, or have it as a kind of badge. Or maybe after having, I don't know maybe 1000 disposable cheap cards, you can trade it for an actual permanent Epic, Rare or Legendary. The thing is to incentivize people to win and get more of those.