Personally I would like to see an auto win if the person you are dueling in a "rated" pvp match walks away from their computer or rage quits rather than needing to finish the game against a CPU. People tend to quit out when they are inevitably going to lose and it would make more sense for this to be in the form of a forfeit rather than making someone waste the time if the other player doesn’t even feel it is worth continuing.
Personally I find playing out another 5-8 turns when you are trying to PvP is annoying beyond belief, as half of the fun is getting feed back on your deck and enjoying a casual conversation about elements.