Arena isn't technically declining, it's just mainly stagnating. I have tried some unusual battles in the past such as a team of tanks against each other, but it didn't work out. We definitely need to do something if we are to stop stagnating unless we're fine with that.

Giving physical rewards would likely breed a bunch of salty behavior and metagaming in order to win the prize, so I'd be against that. We did include win/loss stuff on profiles, which in theory should bring more motivation for people to try to rise in the ranks if people cared about that more.