Has little to do with Matic. Pogba was very good last season (the negative comments here notwithstanding) and he seems to be rounding into superstar form this season. Matic will help when they play other top teams, but right now he is just another big body. Not much different to bigbrush.
Pogba is special. Lukaku is on a confidence high, at some point that will break. Martial is my real worry. If he keeps playing at that level, then they will eventually have a 4 headed attacking monster with Rashford and Martial on the wings with Lukaku up top and Pogba just behind next to Mkt or Mata. That is a very strong front 5 or 6 when confident.
I still think their weakness is defense. RB is older and noticeable slower. LB is good on the ball but a poor defender. And Jones is error prone. SO they have 1 true defender and a great keeper. But unfortunately, they don't play open football against other top clubs. You can expect both Matic and Bigbrush starting in the middle with Pogba agains t other top teams.
It is a winning formula. Attack the small teams with your speed strength and t talent and then bully the top teams with your size and compactness. If they play it right, they'll be in the running come May.
We just need that confidence to break soon and Lukaku to return to been a poor first touch striker.