While fields is an athlete, and a threat to run in read-option plays, he doesn't have the same throwing ability as LJ. Fields has a good arm, but is a bit more scattershot in his throws, isn't as accurate on the move, and his release is slower. He (like a young josh) struggles to throw people open, and will sail some. His pocket presence has been a weakness as well.
As for hall, he's not derrick henry. Which is a good thing.
Same as us - when your teams banged up in camp you tend to have lighter practice loads for guys and lots of guys skip padded days. Week 1 happens and i feel like the game-to-game preparation and practices ramp up a bit.