I don't see Zielinski replicating a lot of the ball carrying that Mkhitaryan does. He can slot in there, but he's gonna be a different type of player. Just like Frattesi basically isn't to be trusted with carrying the ball and we need to play with one of our midfielders as an off-the-ball kind of player, Zielinski on the other hand is ball heavy, recycle possession and distribute out wide. And shoot, he can also shoot.
In that sense, it'll be hard to see Inzaghi shifting from a winning formula to something that would mix things up, even if Zielinski is a superior player to Mkhitaryan.