I think there are some poker analogies that could help to answer this question, but first we need to understand the conundrum of "a good call" in football.
One criterion for a call being good is that it fundamentally gives you the best chance of achieving your goal (independent of the chance of the defense anticipating such a move). A second criterion is the the chance of the defense anticipating such a move. As a general rule, the better a call measures on the first criterion, the worse it does on the second, and vice versa. A third criterion is how well the play could work out even if the defense anticipates it. It is because of the third criterion that the QB sneak on the goal line is called so often - it usually works even when it is entirely expected.
If Bob Stoops had waited for a situation that measured better on the first criterion, it would have measured poorly on the second criterion. And unlike a QB sneak on the goal line, it would have little chance for success if the defense were expecting it. So, there wasn't going to be a better time later. (Ergo, people who claim that he did it "too early" are wrong.)
The fact that it came up only 0.5 yds short is proof positive that it was not expected (i.e., that the first and second criterion were met and the third criterion was n/a).
There is, I believe, a fourth criterion: if the play fails, what do you lose? I think this is measured in terms of field position given to UT. We were returning punts well and the punt was against the wind, so it would be naive to assume that a punt would have pinned us deep. Even so, UT was able to score from seemingly wherever it started. So, rather than considering field position as an indicator of the ease with which UT might score, you could actually view field position as an indicator of how quickly we might score (i.e., how quickly OU gets the ball back). With this view, OU gave up nothing and perhaps gained something by giving up some field position.
In summary, the upside was huge and the downside was low. And since nobody expected it, the odds of success were pretty high. I call that a good bet.
Where is the poker analogy? I am going with a Post Oak Bluff against an experienced and tight opponent. Comment if you have a better one.