The offensive game plan you saw against Oklahoma was much more in line with what Frost ran at UCF and Oregon, minus the tempo.
First drive 8 runs and 6 passes
Second drive 2 runs and 1 pass
3rd drive 4 runs and 2 passes
4th drive 5 runs and 4 passes
half time
5th drive 9 runs and 4 passes
6th drive 5 runs and 4 passes
7th drive 0 runs and 4 passes
8th drive 1 run and 3 passes
9th drive 0 runs and 4 passes.
The last 3 drives are indicative of a team behind trying to score.
But the first 6 drives were pretty balanced, there wasn't a bunch of designed runs for the QB, he ran when he was in trouble and hit the deck or ran out of bounds rather than taking big shots, plus there was the use of the RB in the passing game.
As far as Michigan St's rushing defense, Northwestern ran the ball 38 times for 117 yards and 3 yards per pop. They also abandoned the running game when they fell behind, they were almost exclusively pass for the second half. Miami was almost exclusively pass from the get go, they only ran the ball 24 times with the QB King running half of those attempts and 3 of them were sacks. So 21 rushing attempts in the game. Then there was the FCS opponent, that I won't even breakdown. Bottom line is that while the opponents did not have huge success running the ball, they also chose not to run the ball because they were behind due to their defense giving up big plays for TDs.
It is almost similar to playing Army and then saying you have an awesome pass defense because you held them to 50 yards through the air.