I'm not sure how much they bend things for athletes, but general admission standards at OSU have significantly risen over the years. I have seen recent reports that have their average GPA and ACT scores of incoming Freshman at the same level as OU and Miami. It is becoming a lot more difficult to get in to OSU. When I applied to OU in 1991, OSU was automatic admission to just about any Ohio resident with a pulse. It is no longer the state backup plan.
I think as the links borna show, Ohio State typically is harder to get into than Ohio and is pretty well on par with Miami. A lot of those who don't get into Ohio State's main campus, though, go to one of the branch campuses first and finish at the main campus.