Willian is a much better all-around player. Very reliable defensively, and has a lot of potential to improve offensively. Very quick. Syncs with the team. Schurrle is unpredictable. Awesome at the World Cup (if it were based on actual benefit to his respective team, I would award him best player of the tournament: made an impact on EVERY game he came into, and assisted the goal that won the tournament). But then completely failed to impress at Chelsea. Zero. Salah is a mystery, with not enough playtime to judge. Brings a lot of flare when on the pitch, but not sure what that means in terms of emmm, future potential maybe? I would sell Schurrle while I still can, loan Salah and see how he matures in a year or tow, keep Willian, and buy an experienced winger.