I love the people who think Messi is detrimental to our attack. I have no idea how you could ever come to that conclusion.
Messi is a *FANTASTIC* attacking midfielder. Against a good team with an organized defense, he is a *LOUSY* motionless center forward, and a dead weight until he eventually drops back into his natural role as a midfielder. This is the complaint, about how Barça positions Messi tactically, and instructing the wide forwards to stay on the touchlines to, in theory, create space in the middle for Messi and the attacking midfielders.
I'd be curious to know if Barça has scored any goals this season when Messi contributes from a center forward position rather than as midfielder far removed from the back line of defenders.
Messi can play wherever the hell he likes, but Barça should put one for the forwards who is willing to create off-ball movement up in front of Messi in the center (Villa, Sanchez, Pedro). With one of those dragging the centerbacks around, Messi will have much more space to operate, as well as provide the targets that Messi himself is rarely willing to provide himself.