My own sincere take. Texas will win tomorrow.
Now, I say this having only watched them against Maryland and K State. In Maryland, Texas didn't even seem to know how to tackle. They looked incredibly lame, and on offense were really uncoordinated. But by K State, they seem to have fixed many of those problems, and Manhattan is not an easy place to win, period.
I've watched at least bits and pieces of every Sooner game. We have an incredibly porous defense, as you just pointed out JCG. That is more than an Achilles heel - it's like an Achilles thigh, calf and heel. The Texas offense doesn't impress me particularly but I think they're at least as tough as any OU has faced this year, and for example Baylor lit us up by 33. UT has recently played at least that good, if not better.
I do think Oklahoma will hold their own on offense, and will likely have a few big plays and keep this interesting. BUT, I've seen too many of these RRS games to think that we'll be able to run N-S. Losing Rodney Anderson took us out of that possibility, and besides Texas always comes into this game ready to fight hard at the line. There have been years where we've overcome them at the line and/or torched their backfield, and at times have totally worn them out and embarrassed them big. I don't see anything to suggest though that this year will be like that.
Anyway, turnovers could change all this in either direction. But if I were betting I'd say Texas wins this by a TD.