I don't mind seeing Sokratis and Mustafi try to work on their partnership. That's an issue I think can be sorted through time and coaching.
But I can't see how a player like Xhaka can make it in this team. He can't play on the half turn, can't defend and is slow and rigid. That's a player profile issue and means whoever he gets partnered with has a lot of work to do just to cover Xhaka's flaws.