I like Pickett and wish he wouldn't have asked for a trade, but the idea that he has shown more talent than Fields at this point is laughable.
The dude was a 2nd/3rd round talent that was carried into a 1st round pick by Jordan Addison torching shitty ACC defenses. Once in the NFL, he constantly had problems with sticking in the pocket and regularly bailed out of the pocket prematurely. Even if you want to criticize Fields for a lack of vision (which is true), Pickett was no better. Pickett has the same issues with on-field vision that Fields has.
The two don't have notably different passing/vision talents IMO, the only difference is that Tomlin beat Pickett into being scared with making mistakes while Fields was allowed to go AWOL with the Bears. Fields is at least a major threat in the running game while Pickett isn't. That's why I said earlier that Fields' upside is mediocre passing ability (in terms of starting QBs) while being a major threat in the run game. Pickett's upside is the same mediocre passing ability, he just doesn't offer the run game that Fields does.
It's most likely that neither end up a starting caliber QB, or at least a good one, but I see more paths to that with Fields than I do with Pickett. You might be able to tolerate Fields' mediocre passing ability if he's also putting up 50-75 rushing yards a game while keeping the turnovers down. With Pickett, I don't see anything there that adds to his passing abilities. If you don't think "mediocre passing ability" is good enough for a starting QB, then neither of them will be starting QBs.