I think the main reason Makar's struggling is simply because as opposed to a normal rookie season, or his games last year, everyone knows who he is now after that playoff run.
He doesn't get to ease his way into the season or surprise anyone out there. Teams are targeting him on dump ins, and he's struggling to make the quick plays under pressure. He's got to move the puck a little quicker, or step out from behind the net and skate it out quicker.
He's just hesitating a little too much now trying to figure out what all his options are, so he can make the best one, but by the time he picks one, there's one and sometimes two forecheckers all over him.
He's just got to settle down a bit, and the coaching staff, and guys like Cole and EJ need to give him some pointers about staying in position during scrambles. He's trying to cover multiple guys at times after they move the puck, when he'd be better served just staying in position to block passing lanes. He's just trying to do too much right now. Probably because he thinks he needs to replace Barrie's role alone as a rookie, when in reality it's a committee approach.
He'll get it figured out. He's got 7 points in 8 games without really even playing that well. Imagine what he'll be able to do when the game starts slowing down for him.