I feel like people are having a lot of trouble figuring Purdue out.
It's simple.
If Purdue is up against a team with an excellent or elite DL, Purdue is screwed. Our OL is passable at best, and with scheme we can do alright against average to good DL. But if you have an elite DL, you can shut down the run game and pressure the QB with 4 [and sometimes 3], and drop 7 [and sometimes 8] into coverage, and AOC can't be expected to pass into those tight windows all game long successfully. If Purdue is up against a team that can wear down our defense, we're in trouble. Our defense is good, but we don't have the depth to go 4 quarters against a ball control offense.
If we're up against a team with an average to good DL, we have a puncher's chance. If we can establish at least a LITTLE bit of a run game that requires run support from the second level, we have the skill position players and the scheme to move the ball. If we're up against an offense that can be exploited by aggression, we can stall some drives and keep time of possession on our side, which we need because our offense isn't the most efficient. If we have an offense that can be forced into errors (like Nebraska), even better because we can put on the pressure for that.
Wisconsin killed us by shutting down our run game with 3-4 DL and daring us to pass into the teeth of their 7-8 man coverages, and then on the opposite side of the ball just grinding our aggressive defense into submission. They only threw 8 passes all game IIRC, because why let our defense try to generate pressure and force you into mistakes if you don't have to? Iowa couldn't pull that off--they didn't get their usual turnover margin and couldn't just run the ball down our throats. Nebraska the same--Purdue didn't have a great run game, but Purdue had a run game, and Purdue's defense forced Nebraska into all sorts of mistakes.
Ohio State is going to destroy us. Michigan State, IMHO, will and should be heavy favorites, but there's at least more of a chance for Purdue to create chaos. Northwestern and Indiana will depend on which team makes mistakes, because they have no real talent advantage.