Idea: earning points from wins by your "defenders" in Arena
I had an idea that your champions, used in Arena as opposition for other players, would earn you some small amount of points from defeating other players playing Arena. In a way like earning points from your defenders in Alliance War. But of course a much smaller amount.
Would be fun though, to see your champions passively participating in Arena actually earning you something in return from their success. It would motivate players even more to get a really good roster and add an extra element of multiplayer to Arenas.