Does he? I don't see any great energy, commitment or willpower in him. From what I've seen he often strolls languidly around the pitch, mostly passing sideways and backwards, and sometimes getting caught in possession. I don't see that he's going to take games by the scruff the neck and impose himself on them: very unlike Modric, or Bale, or Alli and many others whose sheer drive is evident. I suspect he'll will find the Prem a huge shock compared to Serie A.
Moreover, I keep hearing that he can't play well in a midfield 2 unless it's with an out-and-out DM - and his performances alongside Matuidi in the Euros seem to support this view. But United don't have such a DM, so apparently that's one role for Pogba out of bounds straight off the bat. This is unfortunate, seeing as Mourinho prefers a 4-2-3-1 formation. It's also not great to think that this "world class" player apparently needs everything arranging to perfection around him before he can play well.
So where is he going to play? The only seeming option is to drop Rooney, the captain, to make way for Pogba in the AM position. But that will result in a storm of Rooney dissent within your squad ... hardly the best way to get Mourinho's reign underway.
Pogba is a good player, if not very versatile. He's got a very good long range shot, is good in the air, is big and strong and can make powerful, driving runs forward He's also got a few fancy tricks and flicks. But does he have the sudden acceleration of Modric, or the vision, intelligence and passing skills of Modric or Carrick, or the energy, commitment and aggression of Veratti? Not that I've seen.
Yes, he's scored some goals and made some assists - albeit in a weaker league. But then so has Alli last season, at younger age and in a stronger league.
All in all I think that Pogba has been greatly over-hyped. He'll improve United, but not by that much.