If we see our cards, we would be very surprised to see how many wasting cards we have. I know wasting cards could be used to enhance heroes, but still we would see hundreds unused cards in our list.
Therefor, it would be very interesting if we have a kind of Loser Competition. The one who lost the battle is the winner. Of course there would be rules, for example :
1. Only Promo and Legendary may get involved
2. No same card in a squad (point 1 has described this)
This way, beginners can come to join the competition, and wasting cards would be very useful.