They have a new OC, are playing a new defense, and have changed some important personnel (QB, OLB, CB).
Their QB is ponderous and has one of the slowest deliveries in the history of football, which is important, because Garcia's quick drops and quick deliveries were instrumental in limiting Ware's pash rush in last year's game (no disrespect to their LT Penn, but he barely had to block Ware to keep him from registering a sack).
But the wilcard is Clifton Smith. He's a very good returner, and he can really change the game if Tampa can keep it close. Hopefully Buehler can get some touchbacks. I wouldn't mind if McBriar sacrificed some distance to kick away from Smith because the Tampa offense just isn't that scary right now. I'd much rather force them to go 50+ yards for a score than to give Smith a run at it.
I still think Dallas wins by 10, but there is reason to be nervous.