I get your idea but I am not sure how you mean it - sacrificing Matic for Pogba means a three man midfield of Fred, McTom and Pogba with McTom being most defensive minded one? Or Pogba being the furthest back as a DLP?
I think, using Juve to talk about Pogba is difficult. They played with a 3-at-the-back formation didn't they? Not sure about it but Pogba was very good next to Pirlo and Vidal/Marchisio. Pirlo took the responsibility to give the team the rhythm, with passes of all ranges. Vidal and Marchisio at the top of their game were awesome players. Workhorses with a lot of quality in offensive and defensive situations. So Pogba was relieved of a bit of pressure which presumably got out the best of him. Add to that that Juve was playing with Tevez back then, another player with an abundance of workrate.
At United we have nobody to keep the team ticking (except for Pogba himself ability-wise) and, even though Fred might have the workrate of Vidal, he certainly doesn't have the quality of the Chilean. Add to that, that Bruno plays differently to Tevez and it gets clear, that the Juve-idea can't be transformed to United 1:1. I'd also add that, to me, Pogba is a player who crumbles a bit under pressure. He is a special player, who excels in pressure free situations, but when the pressure is on, it doesn't really work for as he loses the lightness. He is a senior player now, and maybe he is better with that nowadays but we just don't know.
I also don't think, that McTom would really flourish at the DM position. He doesn't feel comfortable when the whole play is happeing behind, in front and next to him. He lacks the spacial awareness I'd say.
As I said in another thread - getting more bodies in the central areas is the first thing the manager HAS to do. Should have done it one or two years ago. But I don't think Pogba is the way to go. I see Pogba as an option in games that suit him coming from the left. Obviously not as a winger but starting there to drift in. He is a nightmare to create a team around and looking at his contract situation, I would do anything, to keep him out of future plans right now.