#1 Nicolas Pepe (Lille to Arsenal for £72 million)
Things are really not looking good for Nicolas Pepe at Arsenal. The Ivorian was one of the most highly sought wingers in Europe after scoring 22 league goals for Lille last season, and the Gunners managed to sign him amid intense competition from other clubs.
A lot was expected from him, and not just because of his transfer fee. Eden Hazard was signed by Chelsea from the same team at roughly the same age back in 2012, and we all know how that turned out.
Pepe struggled for game time under Unai Emery initially, before he broke into the starting XI, forming an attacking trio with Pierre-Emerick Aubameyang and Alexandre Lacazette. However, his lack of impact in games meant he was dropped soon after.
The fact that he's managed to provide a few moments of sheer brilliance must be all the more frustrating for fans and the manager. In the Europa League against Vitoria Guimaraes, he helped the Gunners come back from 2-1 down to win 3-2 by scoring two delightful free kicks.
Currently, even Mesut Ozil is higher up the pecking order than him. He clearly has the talent to succeed in the Premier League, but he's still got a very long way to go before being considered a success.