I think the jury may still be out on Colt McCoy. In 2006, he had 68% completion rate, 2570 yards, 8.08 yards/attempt ratio, and a 29/7 TD/INT ration. He did have a bad year in 2007, with 3303 yards, 65% completion, 7.79 Yards/attempt, and 22/18 TD/INT ratio. Last year, he had 3859 yards, 76.7% completion, 8.91 yards/attempt, and 34/8 TD/INT.
With his yards/attempt actually going up, this tends to indicate some longer passes, but these numbers don't take into account YAC (Yards After Catch) yards that receivers pick up. His completion percentage going through the roof would back up what Ignatius said. It is very difficult to get that kind of completion percentage without lots of short, controlled passes. For comparison, Sam Bradford had 4720 yards, 67.9% completion, 50(!)/8 TD/INT, and 9.8 yards/attempt. Bradford had almost 900 more yards on only 50 more attempts, and a full yard more per attempt, along with a lower completion percentage. Chase Daniel had similar numbers, with a 73% completion percentage, and an 8.2 yard/attempt average.
So, it does look like something big changed at UT from 2007 to 2008. I suspect it was a shift toward shorter, more controlled passes and letting receivers to more of the work after the catch. Of course, this is not to take anything away from McCoy. I'm sure the huge improvements weren't totally from the change in scheme.