I really think evolving into a 4-2-3-1 will offer us more solidity and in fairness seems to be the default set up across Europe. One of the qualities Dzeko lacked was workrate of the ball, as highlighted by Muller after the Bayern game??, so the addition of that will improve this area. Similarly I think De Bruyne works a lot harder than Nasri and will offer us more protection on the left flank which is always an area of concern. The three I think we will have will be Fernandinho, Yaya and Silva, dropping in, when we do not have the ball.