The problem isn't him having more responsibility, it's when he's played as the holder as he was when Fellaini was paired with him at the beginning of the season. Pogba needs a holding passer for a midfield partner more than he needs two actual midfielders next to him. For example, I'm of the opinion that taking Herrera out and playing a midfield two of Carrick and Pogba wouldn't lead to a big drop in consistency in performances from Pogba. Pairing him with players like Fellaini, Schneiderlin, Kante, Matuidi or Khedira, would be a problem.