I'm a Fenerbahçe fan so I don't "love" Arda although I don't hate him. I just wanted to set expectations here since I know Arda as a footballer more than anyone here, probably. I guess most of the criticism comes from the fact that Barça has spent €41M to get a 28-year old midfielder (29 now) who will never be an Iniesta.
Bad news first, he won't be much improved next season in this system. Arda is definetely the second best midfielder in Barça but he needs the ball and a lot more freedom. I'm 100% sure he plays this way because Luis Enrique assigned him particularly this role. I don't think Enrique will change the whole system because of Arda. Simply, he's not a very good fit for that role and I don't believe Enrique wanted him for this role. I believe the transfer was an investment for the presidential race. Like I said before although he's the second best midfielder and the third most creative player in the team, in this system with the MSN, I simply cannot see a role for him to shine. Actually no creative midfielder can shine in Barça as far as changing the scoresheet goes.
He'll do OK as a sub for Iniesta and Rakitic but that's all. What Barça needed was a true midfielder who could play both ends of the floor equally well. Arda will do the job as a sub but that won' justify the €41M price tag.
As for his "short passing range" and "through ball" comments, it couldn't be more far from the truth. His passing range is great and he's very good at through balls. He only has two weaknesses. He lacks the speed of a true winger to run with the ball in the open space and his fitness can be a problem if he starts to play 90 minutes every 3-4 days.
Individually Arda justfies €41M price tag. However, not for Barcelona. Still his stats will be greater than other midfielders in the team but you won't find that enough, rightfully so.