Really, you mean Mitch McGary has been playing in the tournament AND I'VE BEEN MISSING IT?!
You can make this case with MSU, but they were pretty damn tough even at half strength. But the Michigan team you're seeing now is the same one Big Ten teams saw all year. They lost McGary and had to adjust, and they're still playing without him. So there's no bait and switch on Michigan's part here. And the games played in the OOC had no real impact for UM; they didn't beat any of the top OOC teams they played with McGary (ISU, Arizona, Duke), so it's not like they padded their metrics before losing him for the year.
The Big 12 was hurt by Embiid and Niang going down, no question. But do any of the other Big 12 teams that got bounced early have similar mitigating circumstances?
Personally, I'd call the conference race a wash this year. The Big 12 was slightly better in the regular season and (if KU/ISU hadn't lost key players) the B1G has been slightly better in the tournament (3 Elite Eight teams to what likely would have been 2 for the Big 12).