I refuse to change my expectations. I still expect a win over texas and a competitive big 12 championship game. That is what i expected coming into the season anything less would be a regression. Why should we now change our expectations for less? What we expected before the season should still be the goal, and anything less is failure and it needs to be dealt with. (i.e. if we fail, Cosgroves head should roll) I'm not going to accept less than i expected before the season, because then i would be accepting failure. Just my honest opinion.
I'm not saying just winning the North would be a success. But unless the defense improves a ton, it's not realistic to expect a win over Texas or to even compete with OU. If all we can do is just win the North, then no, I don't think the season will be a success. More specifically, I'll look at it as a defensive failure that dragged the rest of the team down with it (assuming the offense continues to produce at a decent level).