I do not think many (any?) OSU fans think they will challenge for the Big12 title. OU and Texas are both playing on a different level. You are correct that some (many?) are questioning why Gundy did not play Sanders and Brown last year. However, I disagree that this offense is not capable of staying in Big12 games, other than OU and Texas.
Also, agree that OSU should be concerned about the DL, especially if Bundage is not full strength, and blocking Gibson is a concern.
OSU has the better team as the point spread indicates and if they both play at their capabilities OSU should win. However, this a bigger game for TU than OSU and emotions will be high. If Sanders has a good outing he may well be a difference maker.
In the final analysis, as in many games, the team that makes the fewest mistakes and wins the turnover battle will likely win the game.