I haven't seen anything yet from either Baylor or TCU to suggest that they can't lose a game. You can bet that if OU can survive the next six games without a loss, that the game in Waco will be in prime time, and OU won't be a huge underdog.
You can't make much of Baylor's non-conference games of SMU, Lamar and Rice, nor of TCU's games against Minnesota (a 7-point win), and SFA and SMU. I'm not ready to give up on OU's defense. It was OU's defense that kept the Sooners alive against Tennessee after the home team had forged a 17-point lead.
Minnesota's two wins were over Colorado State by 3 in OT, and by 3 again over Kent State. SFA also lost to Northern Arizona and McNeese, and SMU's one win was over North Texas, one of the worst teams in the country. Lamar's two wins were over an NAIA team in Bacone, and a 3-point win over Sam Houston State from the FCS division. And Baylor's upcoming game against Rice will tell us nothing as well.
With Baker at QB, OU should be in the hunt this year, regardless of how you feel about the defense. Tulsa is #2 in the FBS behind Bowling Green in total offense right now. That didn't all come against OU. I won't be surprised if the Hurricane is a serious contender to win the AAC title this year. Tennessee's hangover from the OU loss translated into a 55-10 win over Western Carolina, not a good team, but a result that suggests that the Vols may have some success in the SEC this year.