Yes, OSU's D has been legit against the likes of Akron, Western Michigan and Marshall. I've watched al three games (GF is a Buck Nut). They are talented, like Iowa, and have their issues, like Iowa.
Check out the time of possession against Akron and Marshall - they were beaten by 9 and 12 minutes, respectively, and it wasn't just garbage time. They struggle to get off the field, have lapses in discipline and have been able (so far) to make up for it with sheer athleticism.
That works against Akron, Western Michigan and Marshall.
They play @ Michigan State next week, so we'll see what they look like against a B1G opponent. MSU is better than expected (only loss is on the road to a good BC team), so it will be a good litmus test.
You are correct that OSU will try to do what every team will try to do against Iowa: stop the run.
Iowa just put up 272 yards (6.0 ypc) on the road against a decent and lathered up Minny D in a RIVALRY game with the Goofers hell bent on stopping the run.
How did that game work out?
Michigan threw for 30 yards (50% less) than Iowa yesterday and beat USC.
There's lots of ways to win.
Cheers1