One thing I will say for Hill, in the 2 late-season games where he got any run, he had 2 tackles in about a dozen snaps against the Bears, and 2 tackles including a TFL on a similar snap count against the Bills. For that sample size, that's good production.
His mental state scares the hell out of me, as he seems to want football even less than your average lazy player, but I think the talent is there in a way it never was with Taco. I hated that guy even at Michigan.
With that being said, you can see that look with players where they lose all confidence and just quit, and from there, there's pretty much no hope of saving them. Mo Claiborne storming out of the locker room after giving up a game losing TD to the Rams and Taco getting benched and *****ing on social media are the first two that come to mind. Sometimes a fresh start with a new team can kick-start their career, but I can't think of a Cowboy who lost that mojo and then got back in the saddle with the team.
There's a decent chance that Hill enters the season as a starter, just because we are about to have a straight-up purge on the DL and he's one of the few guys left under contract. But if he gets benched or otherwise gets frustrated, look out.