In the same vein, I think Pogba doesn't have the same role as the players you mentioned. I think you even said it yourself that someone like Thiago has a fundamentally different role and playing style from him.
With that said I agree that he can continue to improve. Within the context of his own role in the team at Man Utd.
I think people don't really know which role he plays. Maybe he himself doesn't even know. As I read, Bruno's arrival lead to Pogba playing deeper, now in a role that's actually comparable to Thiago's for Bayern and that was the case in the last few matches I caught of United. So he's sort of trapped between the two roles mentioned earlier: The free roaming genius a la de Bruyne and the controlling midfielder pulling the strings. As it stands, he's not productive enough for the first and not nearly consistent enough for the second.
If you ask me, you'd improve if you'd have one of the midfielders I mentioned in his stead. One that controls the game, distributes the ball and brings others in the situations in which they can utilize their strengths. Or he just turns into that midfielder and suppresses his instinct to play the Hollywood pass the moment he spots it. He sure as hell has the potential to do so, he even had long sequences in the Sevilla match during which he looked exactly like such a player and it improved your overall play if you ask me.