One thing that has been mentioned on a couple podcasts and been discussed on the board is the stark contrast in the defense's performance between the JT Barrett offense and the Dwayne Haskins offense. Its actually both alarming and a relief given that Haskins is likely gone.
(Some of these numbers might be slightly off as I was doing this mainly by hand)
In roughly 1.6 games against Don Brown's defense (only regulation, OT is too much like counting penalty kicks as goals in soccer), here are the numbers of JT Barrett and the OSU offense:
Team: 415 yards, 24 points, 6-25 on third down
JT Barrett: 18-40 154 yds 1 int (passing) 45 - 192 2 TDs (rushing)
Honestly, its hard to imagine doing much better than that against Ohio State. This also comes with an extremely pro-Ohio State whistle (OSU was booted off the field on their last drive that got them to 280 yards in regulation, but the refs decided to call PI, similarly, they received some pretty shaky calls in the first half of the 2017 game that Joel Klatt mentioned during the broadcast) and good fortune (having to drive 6 yards for their only TD in regulation in 2016, Josh Metellus dropping an INT that hits him directly in the hands in 2017).
Another way of looking at it: Barrett led only 5 drives out of 19 relevant drives that were over 50 yards. He led only one TD drive that wasn't a gift (two gifts: Speight's interception in 2016 and the Hudson penalty/Metellus drop in 2017), a 53 yard drive in 2017.
Its truly maddening that Michigan was not able to win either of these games. I suspect the reason for losing the 2017 game boils down to the following (Haskins and team numbers, 1.4 games):
Team: 782 yards, 72 points, 10-18 on third down
Haskins: 26-38 490 yards 6 TDs (passing) 10-58 yards (rushing)
9 out of 14 of Haskins drives were for over 50 yards. 13 out of 16 relevant drives (!) led to the opportunity of points (including missed field goals), even if some were short fields in 2018.
Haskins also didn't benefit from any kind of referee shakiness. If anything, in the 2018 game edged Michigan's way.
Long story short: Even when they are unlucky (losing their starting QB), Ohio State is lucky against Michigan. I'm of the belief Haskins' throwing ability both sealed the 2017 game and (of course) won the 2018 game.
However, with Haskins likely to turn pro and Martell looking more like Barrett than Haskins...I think we should see a reversion to the 2016/first half of 2017 performance at least schematically from the defense next year.