#4 Squad depth & tactical options
In recent years, Wenger has addressed long-standing concerns about squad depth. Elneny, Xhaka, Ramsey, Coquelin, Cazorla for midfield positions; Ox, Ozil, Sanchez, Iwobi, Walcott for attacking positions; and 3 capable strikers in Lucas Perez, Giroud and Welbeck.
But an injury to Cazorla took a lot away from this side; Wenger's switch to 3-4-2-1 was part of his attempts to move the creativity from deep that Cazorla used to provide towards in advanced areas of the pitch.
Lemar's acquisition could be a tactically significant one. He can convert to a wingback like Ox did, or flank Ozil on one side with Sanchez on the other side in a 4-2-3-1; he can even play as one of the deeper midfielders in a 4-2-3-1 to provide drive and creativity from deep.
Arsenal's squad depth has improved leaps and bounds in recent years; now it is up to Wenger to ensure he leverages it to make Arsenal tactically less predictable.