I think it's really up to Juve-Roma now. Roma's best shot was to buy him now, since their relationship with PSG is probably better.
I don't know, it looks 50-50.
Roma is known for developing and opening space for younger players.
Juventus however while not known for that, have the 2 best young French players of current times. One of them is 18, and started in the first league game. If Coman gets enough space from Allegri (at least being the first option in rotation ahead of Giovinco), Rabiot, who is a close friend to him, would probably prefer to join Juve.
His mother seems to have build some relationship to Juve's managers. But Roma probably had a deal agreed with them too.
IMO, if he signs for free, he signs with us. If he leaves in January, PSG will give preference to Roma.
So it's probably up for him now. If he really wants to play in the 2nd semester, he'll probably go to Roma. If he's patient enough to wait, he'll join Juve in one year, where one of his closest friends and apparently a big hit is.
The influence of Pogba's and Coman's experiment should be a huge factor.
But if PSG decides to sell, they'll do it to Roma, I'm sure. We screwed them on the Coman thing.
I feel he'll go to Roma. Our midfield is much more crowded than theirs.