Mikel should play as a holding midfield player because I feel that he's good there. I think apart from his consistent untentional challenges, he's a pretty solid player. I think the only reason why Mikel didn't play so well against Liverpool, is because he got booked in the first few seconds of the game, and had to be careful. If you think about it, a holding midfielder is renowned to go in for tackles to win the ball, a wrong move could get you a second yellow and get you sent off. Essien and Ramires should play off Mikel as two central midfield players. I'm starting to believe that Ramires is getting a grip in the midfield finally, and he's able to win the ball easier than he did when he started. Essien has gotten better, but he is still making sloppy passes in the middle, which really needs to be worked on.