From what I have seen of them this year, the Cowboys are not good enough to sit back in coverage against the Pats, so an aggressive rush scheme would be their best option IMHO. In particular I am unimpressed by their safeties and linebackers in covering backs and TEs. I see a good day for Gronk, Hernandez, and Welker in this one (I know, I didn't list a Pats RB, but Woodhead and Ridley are question marks for me going into this game, I don't have a feel at all for how O'Brien deploys them).
While it's important to remember the performance of Rob Ryan's Cleveland defense last year against the Pats, I think the Pats are in better position to handle that - especially if Vollmer plays and is reasonably close to full strength. Dealing with Ware will be no picnic, that's for sure, but while the Pats have given up some pressures here and there (especially last week), in general that's been against teams with better secondaries than I think the Cowboys will put on the field Sunday. Also, say what you want for "The Rat," but I have to think his input was very significant in the Cleveland game last year, it wasn't just Rob Ryan i don't think.
Bigger question for me is whether the Pats D will make enough plays against the Cowboys O. I know Romo has been pretty bad in a couple of their gamees this year, but he will have Myles Austin back, and the combination of Romo's mobility and Witten's effectiveness in finding seams is what I'm most worried about.