One big problem for Messi is Barca's philosophy of playing, and it being vastly different from what Argentina plays. Messi is Barcelona football at it's finest, and that involves a high degree of trusting your teammates. Henry said it once, that he has moved position one time to get more involved in the game and Pep literally yelled at him and said he needed to stay in his place and trust his teammates to make the play for him. Henry then vacated his position one more time in search for some action and Pep subbed him. Just like that. And it was fucking Titi Henry.
You keep your position, and wait for your teammate to do his job. If everybody does his job then the ball gets to you, and it gets to you where and when you can make something with it. That is the way Barca plays on the ball. Players trust each other to do their part. But for this system to work there has to be an unique understanding between everyone (from CBs, to FBs, to CMs, to Forwards). That's how the ball circulates. The ball moves a lot, players less so in positional, because they have to claim space and stretch teams. Now, this is more or less the football Messi knows by heart. He knows that if he waits in his place, the ball will get to him. Iniesta, Xavi, Dani Alves, Busi, they will make sure that this happens and that Messi is found with very good, high-quality passes quite often. He is activated by one of his teammate (most often Xavi who was the main player responsible for turning a neutral action into a potentially dangerous action). Messi was the player who would then turn a potentially dangerous action into a dangerous action or a critical action.
Now, back to Argentina. The system doesn't work here because the players don't know it, and even if they did, their quality doesn't allow them to activate Messi in a potentially dangerous position. That is why Messi must adapt, and try to forget the Barcelona way of playing. He's dealing with less skilled players, slower football brains. He would stand in his place like he did in positional at Barcelona and he'd spend minutes without sniffing the ball (there's a video from last year's game vs Chile when Messi had a lot of space at times, but his teammates were just not clever enough to see those gaps). Because the piece that has to move the ball from Rojo (example) to Messi is not Xavi, but Banega, not Busi or Iniesta, but Biglia. Trusting your teammates in positional play only works when these teammates have the necessary quality to do execute their role time and time again, like clockwork. If they don't have that skill, you only have few options. Do the whole job yourself, like dropping deep and taking the ball from the middle of the park, in which case you set up Higuain and Aguero so they can miss chance after chance, or you try to do cycles of 4-5 dribbles, instead of 1-2 dribbles (which would've been the case if you got the ball higher up the pitch). Problem is it's almost impossible to dribble 4-5 chileans in a row. This is not FIFA. We're talking about though defenders, strong and committed, that are not at all easy to get past by. The best option for Messi imo would be to stay closer to the opposition's box, but move more off the ball and make himself harder to mark. He needs to receive the ball between the two lines of defenders set up by the other team. Take command of his team more, stop waiting for Biglia to do his job (as it would be the case if he knew how to pass right) and start to treat players Biglia like the mediocre player he is, one that only passes when he's sure he won't miss it. Work overtime to make sure even a Biglia can pass you the ball.