Iaquinta can also play as a RWF in 4-3-3, or as a SS, that's why he's compatible with DP, trez and Amauri, while Trez and Amauri didnt merge together, so if DP is injured/tired, Iaquinta has to play
I want Aquilani for sure, but remember that he's not the king of the center field at Roma, he plays next to De Rossi and Perotta, which makes things easier than playing next to Poulsen