Its possible that they are impressed with him because he's a rookie but some of the comments seem as if its more than just - he's doing a good job as a rookie. Everywhere he has been people have said his leadership and intangibles are off the charts. So I'm getting the impression that he is very special in that way. Guys that are like that seem to have success wherever they go and get the most out of those around them.
I think you're probably right about that. I suspect he's a more natural leader than Tony ever was in some ways. Tony led the team in his own way, but it came from being so smart, being an absolute jedi on the field, and by playing through anything that happens to him. Once you get Witten in your back pocket, you know you have the whole team. You can also see clips of him mentoring Dak on the sidelines during games, and hear from the tone that he's still the lead dog in a lot of ways.
But I don't doubt for a bit that Dak's got a swagger and a natural leadership quality and a swagger that Tony never had naturally. It's just a personality thing, and it's that 'it' factor coaches have been raving about and the players all are mentioning. Again, it's a great quality to have in a young QB.