The timer would still be present to regulate turns, but more card effects could be implemented this way. This way also, when a player plays a card, the other person sees it right away. Now obviously I don't know how this game was programmed, but even players with great connections can desync, depends on how the game was made of course, but this could possibly help if done right.
So if it is your turn, you are the only one that can play cards, like normal, but the other player sees each thing being played, but when you play a card specific for this change of course, that forces the player to choose lets say one of their creatures in play, then they would be able to right away.
So this would not create balance issues, and players do not have their turns at the same time. Was tired when I made first post, sorry for misunderstanding.