On the season, Matt Cassel's 63% completion percentage, 1:3 TD to INT ratio and 62.3 QB rating would not seem like an upgrade for the Cowboys over Brandon Weeden's 72.4%, 1:1, and 92.1.
Yet, I think I'm espousing something that's not too uncommon a sentiment right now, which is that Cassel did a better job than Weeden has. Simply put, Weeden's game, which is pretty check-down based, may be conducive to high completion percentages and low INTs but it is not conducive to anything else the Cowboys are doing. Whereas, Cassel's willingness to air it out a little bit, though he looked like a QB who lacked the skills to do so Sunday, is.
In other words, it is not entirely a coincidence that the Cowboys managed only 100 yards rushing in Weeden's last game and 233 against the Giants. It's also not just because Darren McFadden might be better than Joseph Randle, or that the Cowboys were playing the Giants instead of the Pats, and because McFadden got 30 shots at it.
It was because Cassel's attempts to spread the field at least made the Giants' defense spread out a little bit which arguably gave McFadden room to run. All four of Devin Street, Brice Butler, Terrance Williams, and Jason Witten had at least one reception of 25+ yards. In Weeden's last game, Cole Beasley was the leader at 21. These things are pretty well related.
And unfortunately for the Cowboys all of that just enlarges the pathos of a lost season. If the Cowboys could almost beat the division leading Giants with Matt Cassel throwing to Terrance Williams, and might have beaten them if not for a late special teams TD by old friend Dwayne Harris, it just shows you the leaps and bounds the Romo-Dez led Cowboys likely would have put the Cowboys ahead of everyone else in the NFC East. As it is, they're now two full games back and with games against the Seahawks and the Eagles coming up, it'll probably get worse before it starts getting better.
That being said, if Dez Bryant is as ready to return, as he says he is, there's no question a QB who can air it out a little bit is the right choice for Sunday. And if Cassel can knock off a little bit of rust, and make a few more throws, I wouldn't be surprised if the Cowboys still had a shot when Romo finally makes it back.