I'm of the opinion that Troy is (or at least used to be) incredibly harsh towards Cowboys' QBs. Just seemed like when he would commentate on Cowboys games he was particularly thorough in his scrutinizing of Dallas QBs. Not that he was wrong, but it was a bit much at times. I always kind of thought it was a, "look at this kid doing a disservice to the job I once had", type of attitude. Or maybe he was more emotionally attached to the team and to this particular position at that period of time.
That said, him giving positive reviews of Dak is noteworthy for me. Maybe Troy is less emotionally attached at this point in time so it means nothing, but I think Troy's opinion is worth something.