He is fine as long as the game is one where we are in such command that his rightful place is hovering around the final third. Its only where a game demands a degree of positional responsibility, awareness and, dare I say it, actual midfield play, that he becomes an utter liability. In other words, this coming week at Chelsea.
Any other manager would change the central midfield for the Chelsea game. Wenger will pick Xhaka and Ramsey as long as they are fit and we know exactly what will happen.