There are serious concerns about Prescott's arm strength, QB awareness and accuracy up to this point in his career; he simply cannot make the NFL throws and has QB tunnel vision. I think it's safe to say he has regressed since his rookie year and this is alarming, especially for a QB expected to be the "franchise guy."
With that being said, at this point in Dak's career, he reminds me of Tim Tebow's struggles in the NFL. If the Cowboys want to be smart about this, they'll ride out this year with Prescott, clean house with the coaching staff (other than Kris Richard) and begin looking for a true franchise QB in the 1st round next year.