Yeah I like the arena token idea too! However, it's not going to change some people's opinions that the arena is monopolised by people who have access to the most expensive epics and LE sets that give the best stats. You could still combine the common/rare/unique tourneys with the arena token idea and implement them both. Don't see how that could hurt anybody
Contrary to popular belief, someone who uses expensive epics in the arena can easily be beaten by someone wearing common items. You just need to guess what stats your 'epic' opponent has, then find a counter setup. There's no monopoly in the arena. Except, it may seem like the players who frequent/ are addicted to the arena win more than the players who participate every so often. With good reason. If you fish in a pond everyday, you're bound to catch something.