I don't think we should have signed Arda because he hadn't really played in the position and role before that he has at Barca, BUT I don't think anyone imagined he'd still have such an underwhelming start like this.
Pre-season will be vital for him when it comes to finding a role in the team, BUT.....if I had to bet, then I'd put my money on him moving out in 2017, with another midfielder being signed, even if he does well next season.
Unless he of course performs at a higher level than he has ever done and anyone ever expected of him ofc.