Serie A football is far far more tactical and slower than EPL. You see how Capello, Conte, Ranieri, Carlo A, etc. set up? That's all of Serie A with the exception of Spalletti. It was a better fit for Ibra and Mou. Here, on ball pressure and transition from attack-defense and vice versa is a lot faster.
Other problem is that players who have been in EPL for a long time and/or been developed here are just poor tactically speaking (generalizing). In Serie A, the better teams are so well oiled that everyone knows automatically where the others are going to be and everyone keeps tactical discipline. In EPL, that's just not there. You see Pogba and Ibra having some difficulties because they can't anticipate what their teammates are going to do. So you see a lot of hesitation and missed passes by both... and they NEVER had those issues.