He sucks as LM. He just runs and doesn't really have the skill to beat his opponents. I mean, he has this thing where he looks down and just runs straight forward with the ball. He could be the perfect LB in the future but he is not good enough to be a LM for Juventus.
He does not "suck" at left-midfield. That's his natural position and he does have the pace to cause trouble. Whenever he got down the flank last season I liked what he saw, along with the crosses. He can put a decent ball into the box for us.
Even though we probably won't be playing with midfield wingers very often we should still have a few in the team just in case we need more flank presence. Salihamidzic, De Ceglie and Camo should be enough, along with Seba if we need an attacker.
Having a player who can play two, perhaps even three positions on the left side of the field is useful option to have. Lets not deny that here.
I haven't seen enough of him at the Azzurrini level to judge him in a central left role though.