I'd only got 4-4-2 if Pienaar was in the middle pulling the strings, because it would'nt work and hasnt worked in the past without a player like that (Arteta tended to be playing on the wings and we had 2 DM's in the middle).
The thing with the 4-3-3 is that you get to utlise you attacking midfielders in 2 different ways while also having a solid player to sit off. You bascially have your 4-5-1 but 2 players in more advanced roles depending on how the game is ran. Fellaini and Cahill alternating with Billy and Pienaar, and when they do that they suck into the middle.
You look at Citeh -
Given
Richards Toure Lescott Bridge
Wright Philips Ireland Barry
Bellamy Adabeyor Robinho
The only ball winner, as such, is Barry, but its what they do...and what Chelsea are tending to do also. But again, its about ball rentention and backing players up. Those teams have better players at it then we do.
If we go 4-4-2 though, we do need that player that's going to spread play.