I imagine that with the money we spent on him, people were expecting him to come in and boss some of the opposition forwards ... in reality, he's not going to walk into this league and oust Agger (a Barcelona target), Skrtel (prem experienced, learnt his trade from Carra and probably one of the top cbs in the league on current form), or Toure (11 years in this league winning trophies with top teams, 106 int'l caps, and still a colossus).
You compare him to the 3 above, and he won't come out looking like a 15mill signing. In fact, he seems to have slower feet than Carra did, and also seems to rely on his athleticism more than his positioning. However - he's got the potential to be better than all 3, and his style is much better suited to the new breed of Drogba style forwards that keep bullying our backline. Strength, pace, and ariel ability. Let's give him a couple of seasons.