Well if you actually watch Chelsea, you'll see how stifled they are, Hazard is more or less given a free role, as Matic tucks over to the left, and azpilicueta rarely goes forward, Willian is an exceptional player, and I'm amazed at how you can't see that?
What exactly is "exceptional" given that he rarely scores and assists? I never see him beat a fullback, I rarely see him make incisive passes, he's not very good at finishing, so again what is exceptional? The stifled thing is just an excuse. I've heard people say so many times that so and so will improve under a new manager with a more suitable style and it rarely happens. Really good players tend to show their quality under any manager.