There's a big IF regarding Essien... If Essien were to return to 100%, then I would remove Romeu, Ramires and Mikel and just play two attacking mids in front of Michael in the 4-3-3. This is because he can be the shield, and also bring the ball out of defense quickly. We don't yet know in what capacity he has returned, and that's why we're in this dilemma. Ever since his previous injury, he seems to have lost some of the tenacity to break up attacks and win the ball back. That's part of the reason why we used to concede possession so cheaply last season. Like Jaimin said, Essien can't just walk back into the starting 11 without proving himself. The same would go for Gary Cahill. Him and Terry should have a good understanding from the England games, but the defense doesn't revolve only around the centre-backs. Also, its not fair to write off Luiz just because there's another option.