Two words Anthony Boone. ESPN hypes him a good deal and he's one of the only QB's coming back in the Coastal this year. Vegas sees him for what he is, a dude who threw 13 TD's and 13 INT's last year.
No, Vegas sees Duke as a team to whom a lot of people (like many of you obviously) give little respect. And remember their goal isn't to predict the winner, but to get 50% of the people to bet one way and 50% of the people to bet the other so that they have no money at risk.
If you want to know why Duke is ranked above us, they went 10-4 last year. We went 7-7.
Yes, we beat them but they won the division.
We got similar respect from some in 2010 after winning the ACC but there were likewise many who thought we were a flash in the pan and wouldn't win another ACC title.