I'm as worried about this game as any. The Skins offense is rolling right now, and if Hopkins hadn't choked in London, they'd be 7-3. Cousins is playing great, and they have 5 tremendous receiving options in Reed, Crowder, Garcon, Jackson and Davis. Rob Kelly has given them a consistent (but not spectacular) running game, and their OL is legit.
If the Cowboys don't pressure Cousins, he's going to make big play after big play against the Cowboys's depleted secondary. Scandrick ain't the same player right now, so it's on Carr, Brown and Jones to play A+ games and hope Wilcox and Heath don't give up big plays.
However, if Dallas can continue their time-eating, physically demoralizing, mistake-free (for the most part...1st and 30) 10+ play drives that take 6+ minutes, then they'll be in good shape.
I think the game will come down to who has the ball last wins. Hopefully it's Dallas.
One last note, the Cowboys under Garrett are 2-4 on Thanksgiving with wins against a terrible Miami team in 2011, and a terrible Oakland (Matt McGloin picked them apart) team in 2013.