You would chose Laporte, a £50m signing who wasn't even selected to go to the World Cup, over John Stones? Where is Benjamin Mendy?
Walker can drop back and cover the RB position, Laporte isn't a LB and so you have just left the entire team exposed on the left hand side and Sterling isn't defensive enough to drop back and cover.
Your team isn't balanced enough to counter the big teams in the Prem and in the later stages of the Champions League.