I don't want to take anything away from Gerry Gdowski or Bobby Newcombe. However, I don't think either was a "great" passer, despite what their passing numbers might suggest.
In Osborne's offense, the run game started everything. It was overwhelmingly powerful and defenses had to line up to stop it. They stacked the box, the safeties played up, and the whole defense was within 5 yards of the line of scrimmage. The passing philosophy involved getting defenses to bite on the run and expect it so much that you could slip a tight end behind them un-noticed and have them wide open over the middle. Typically, the ball was underthrown so that you were assured of a completion but no yards after catch rather than trying to hit the receiver in stride and risking overthrowing him.
I don't know how Newcombe or Gdowski would grade out under PFF's grading system, but I know for sure that Adrian Martinez grades out extremely well in the passing department. Here's a little graphic about "Big-Time Throws" showing AMart as a freshman was 2nd in the B1G among returning players:
And here's a discussion about what "big-time throws" are:
What is a big-time throw?
In its simplest terms, a big-time throw is on the highest end of both difficulty and value. While the value is easy to see statistically, the difficulty has more to do with passes that have a lower completion percentage the further the ball is thrown down the field. Therefore, the big-time throw is best described as a pass with excellent ball location and timing, generally thrown further down the field and/or into a tighter window.
The idea of the tight window can often bog people down as they ask, “Why do you want your quarterback to make riskier throws?” But it’s less about taking a risk and more about executing a pass that perhaps makes up for a deficiency on the offense. If a receiver can only create a tiny window of separation and the quarterback can put the ball in an optimum spot, he’s now created a big-play opportunity despite the receiver, not because of him. “Throwing receivers open” is a necessary skill at the NFL level, and big-time throws are just one way to capture it statistically. Sometimes difficult throws are necessary, because every offense will end up in unfavorable down-and-distance situations at times, and completing a regulation 3-yard out doesn’t help on 3rd-and-15.
Furthermore, we may see big-time throws under heavy pressure, turning a negative play into a positive, making a tight-window throw in the red zone where all passing windows are compressed, or perhaps throwing the beautiful 50-yard bomb down the field with good ball location. Hitting receivers #InStride is also important and more difficult to achieve the further the ball is thrown down the field. Well-thrown downfield passes that allow for further catch-and-run opportunities fall into the big-time throw category.