Hi
2 Players can build a grp and use voice over launcher and Choose ther Class and Build ther Decks like regular adn queue for the grpd regular ladder.
its also possible to play casual and queue solo to team up with another player.
Maybe a lobby to search for other players would be interesting for this and he regular format.
So we have 2 vs 2
The game starts as usual and one of the Team Mates in EACH Team get rolled as
Player 1 and the other as Player 2
I will call them for simplicity in this topic P1 and P2 in Team Red, and P1 and P2 in Team Blue, for better explaination
The game starts With Player 1 Team Red and he can make his play.
When he is finished, he gives the turn over like regular to the opponen Team.
Now Player 1 from Team Blue can play his card.
And now the magic happens 
When Player 1 from blue Team has finished his turn and gives back to Red Team:
The Player 1 From Red Team will vanish. He will dissapear and his hand and Deck too but the board stays same.
Player 2 from Red Team will appear now on his place, with his own hand and deck. He will be able to make his play now.
But the board stays the same.
When he is finished he gives turn over again to Team Blue wher also now the PLayer 2 appears with his own Deck.
We play basicly a regular match but on each turn 2nd Players appear.
This way we would experience a 2on2 game mode finally with the social component of playing with a team mate and even talk in Voice about strategie and the next moves.
I can see 2 major challenges today why we dont get a 2on2 mode.
1 is the UI client to stay simple as it is. Which can be solved with this mode.
- Broken combos which can break the player experience.
This need to be watched and for the 2on2 mode fixed.
But imagine the possiblities.
You could finally play a real pure Heal PRiest, a Tank Warrior. A double dps combo. It would feel like in old WOW days when you team with a friend up in 2o2.
Feel free to give feedback !