I think they have a tougher schedule than OSU... but when you're talking about top 4 teams, you *can't* just look at overall win/loss.
An 8-4 team has maybe a 10% chance of being a top 4 team. If you're not playing other contenders, I don't care if you beat them or a 5-7 team. If you're Alabama or OSU, *either* of those games should be a cakewalk.
For ranking the top teams, one win against a 10-win team is worth three against an 8-4 team, easily. Seriously -- would you rather play Wisconsin twice, or MSU once?
OU has wins against other contenders. So does MSU. That's what should matter for a "tough" schedule for a playoff contender.