It's not as simple as that. Sure the width from full backs would help, but if you do not have intelligent attackers, you will just find the fullbacks recycling it back to the midfield every time. Which is what we see time and time again.
Willian and Pedro wouldn't all of a sudden improve their decision making under Klopp. The former was never a top player and the latter is past it. Look at the 1st leg away to Slavia It was utterly embarrassing the lack of ideas we had in the final third.
As opposed to Mane, Salah and even Firmino, who honestly goes unnoticed. The way they move off the ball and their direct nature is why they are so threatening. Firmino is a vastly intelligent player and I hope our next striker has the same technical ability as he has. He would be perfect under Sarri.