There is not a single signing he has made where you can say that that player had made more of a difference than another player excluding Nabi. Those 3 seasons where the spine was peak and included the CL and PL win....each player amongst Allisson, VVD, Fabinho, and Salah/Mane were critical, take away Fabinho...well you got what you saw last season, take away VVD and you got what our defence was like last season Pre Qatar WC. Take away Salah, well you see what happens post AFCON Salah in cup double season....see what happens when you take away Bobby and Sadio ? You can have an attack with no fight.
We just dont have someone we can call his best signing.