This may or may not be impossible if Spectate was only set up for player-vs-player, but I think it would be nice to be able to watch our arena deck play the opponent if it's playing someone. Perhaps have a button that lights up on one of the sides that shows that your deck is being played, and click on that to either open a new spectate arena window or go into a spectate mode in EtG. I realize this is not a pressing issue, but it would be a nice feature to have and would help players (or me at least) tweak our decks because we'll have some idea of what they're failing to.