Argentina are a mess tactically, and Messi doesn't help because sometimes it feels like he's hiding from the ball or he goes and stands far away from the action. When he gets the ball, it's a different matter - he shows more a lot more intensity than he does at Barca, but the rest of the time it's like he's not even on the pitch. For instance, you barely see him keep up with his teammates on counter-attacks.
I'm not saying his individual level drops, but it's a more erratic and less predictable Messi with Argentina. And he suffers from it because his best play comes with combination with his teammates, which is not possible when you have ball-hogs or not enough time to develop chemistry. The past 3 World Cups have been won by teams whose core is formed with players from the same club. Juventus and Italy in 2006, Barcelona and Spain in 2010, Bayern and Germany in 2014. There's a reason it happens. Unfortunately, this is and probably never will be an option for Argentina because their best players go to European countries, and no European club (bar possibly Inter) will ever have an Argentina majority in its starting lineup.