Pogba is talented and has all the ability to perform in a Pep system, yes, but it is the decision making that defines a player and Pogba's as far away from a Pep midfielder as it gets in this regard. Pogba takes far too much time on the ball, often refuses to play easy sideway passes. Instead he stubbornly looks for decisive actions - a key pass, a dribbling, a long shot etc. and he often takes them even if the odds are not in his favour. This is like the antithesis to Guardiola's idea of football. How often was Xavi or Iniesta in a situation in which they needed to shield the ball? Pogba constantly gets himself in situations where it's easy to press him and in which he has to fight for the ball physically. Players like Xavi, Iniesta, Gündogan, Kroos, Modric, Bernardo Silva, Thiago, etc. don't even allow opponents to get so close to them. They have other midfielders chasing their shadows for 90 minutes through positioning, reading the game, quick reaction times and faultless technique, even if it is not as spectacular as Pogba's occasional Joga Bonito skills.
And while it is true that de Bruyne plays in a somewhat similar fashion at City he's by no menas as extreme. He takes long shots and looks for key passes and their successful passing rate is similar, yes, but de Bruyne doesn't lose possession as often, plays less long balls and most importantly doesn't cling to the ball like Pogba does. Instead he fits seemlessly into City's quick passing flow, like Messi did in Barcelona's (who has similar passing stats and occupies similar areas on the pitch to de Bruyne, by the way). That aside, it would be a decision between Pogba and de Bruyne as the idea that Pep would play two midfielders averaging 80% successfull passes simultaneously is completely ridiculous.
Ah, and I think that this Pogba hyping gets a little over the top. Yes, he's got superb skills but saying that he's got the most ability of any midfielder in the world isn't true. His technique is at times inconsistent and overall not better than that of Thiago, Modric, Bernardo Silva, David Silva, de Jong, Arthur, Verratti. I'd take Pogba over any other midfielder in a system that aims for counter attacks/quick transitioning but in a Pep system, there are easily 10 players in the world I'd choose ahead of him.