This is a fair question but also a legit one, with regards to his development. It can really go either way. Juve and PsG are built very differently, from the ground up. Juve are built more like a team and play as a unit while PsG are fragmented pieces of prima donna playing together. Pogba at PeG will have a lot more competition, especially with people that are of a similar age. He will also be in an environment which won't focus as much on him comparatively, and most importantly, things will be a lot more political in the dressing room.
All of those things combined don't necessarily give you enough room to express your best football. My personal feeling is, Pogba will get a lot more attention in France, in a manner that can distract him and since he's an impressionable age, it could also make him a big of a modern day football arrogant prick of a player. For eg. I see Cavani struggling more because the forward line is not built around him like it was at Napoli. He's still a hell of a player though. Pogba will face some of these problems, either individually, or collectively, and that can have some bearing on his ability as a top rung footballer. Needless to say though, if he asks to leave, I won't wish him well at all.