Shkodran Mustafi
Signed from Valencia for more than £35 million pounds, he started his Arsenal career with a bang with 18 wins without defeat. He formed a formidable partnership with Laurent Koscielny in the heart of defense, but things have gone downhill since then.
He is the anti-Van Dijk, instilling zero confidence in the people around him, but has horrendous mistakes littered in almost every appearance in the Arsenal jersey. He is far from world class, and rumour is that, Emery is desperate to ship him off in the summer. Replacing him with a world beater like Koulibaly will propel Arsenal back to the top.
Mesut Ozil
Undoubtedly, the most controversial player on the list, Mesut Ozil is one of the best players in the world in his position. His vision, passing and creativity make him a joy to watch, gliding across the field, creating chances out of nothing and reminding us why football is called the "Beautiful Game". Signed in 2013 for €50 million, he was the signing that marked Arsenal's intent to become world beaters.
He has scored vital goals in big games but he has also played "Houdini" plenty of times, going missing when Arsenal need him the most. He is a confidence player, who needs a good environment with plenty of support from the coach, players and media to perform. That is not the case lately, especially after being ostracized in Germany and retiring from the German team.
Unai Emery doesn't seem to think he fits into his philosophy and future plans, barely playing him. Though he is 30, his playing style isn't based on physicality or pace, which means he has quite a few years left at the top. This means it is not too late for Arsenal to cash in on him. Most importantly, he is is the highest paid player in the Arsenal squad with £350,000 a week, which has disrupted Arsenal's wage structure.
Arsenal players are asking for more money (Aaron Ramsey), which Arsenal cannot afford, nor are they able to attract new players due to FFP restrictions. This would be the last summer Arsenal can get good money for Ozil and they should definitely sell him.