These changes won't solve all the problems and bad behaviors in dueling, but would go a long way:
1) Make the matching process, all the way up to the first move, blind. This will prevent some of the gaming that goes on trying to avoid certain players in the queue. It would also help protect against opponents stacking their decks against a known opponent.
2) Cap the wait time for arena matching at 10 minutes. At the end of 10 minutes, you get matched up with the best possible fit no matter what. This should help lessen the number of players dumping rank to get matches, which is now an epidemic. I can tell you as someone with really high rank, I can understand why people throw matches. It is really annoying waiting around forever for a match.
3) Flatten out the points awarded scale so that there is some incentive for dueling below your rank. I would recommend a minimum of 10 rank awarded/lost no matter the match.
4) Build in some sort of cap on deck size or other mechanism to make it a little more difficult for people trying to throw matches for rank or tickets. Basically treat anything below that cap as a fled match.