I´ve got an idea that should be mentioned I guess. That would bring a lot of joy to play with your friends, if only there were a mode you can play some 2v2 arena, absolutelly random card pick for both players, they would both be playing on the same turn, just cooperate with the cards they got. That would bring so much fun to the GAME! 
The question is wouldn´t be the table small, too much low HP? Well this question is left unanswered to Blizzard. Also this question should be solved/balanced very easily.