As a Sooner fan, I have to agree concerning our defense. I think you were too generous with LB Murray...he's not fine.
Watch the Big XII title game again and just focus on him. It's embarrassing...I don't know how you fix that. It's really hard to watch.
I don't think our secondary is as bad as lukewarm scrotum sweat. Don't get me wrong; they're bad, but our front 7 didn't do them any favors. I think Tre' Brown would be a decent player on a real defense. He sure enjoyed the Big XII title game.
I thought OU's offense would take a big step back last year...If you would have told me that the Sooners lose QB Mayfield, TE Mark Andrews, and RB Rodney Anderson and still average the most yards per play (10.4) in the history of CFB, I wouldn't have believed you. So, I will defer to Riley's prowess even though I really think they HAVE to come down a little this year due to the O-line.
As far as predictions, I don't think anyone gets through the schedule unscathed...my best bet is a 3 way tie with OU, TX and ISU having 2 losses each. Something like that,...should be fun.