I think part of the problem with the Big 10 isn't that it's a weak conference. It just hasn't had a juggernaught of a team that transcended the conference like the Texas, Florida, USC, and Oklahoma teams have done in the last decade or so. Those are some of the best teams in the national eye and I think their conferences received a boost because of it.
Iowa nocked off PSU, Wisconsin and took OSU to overtime with a rookie QB in his first start. Those are three pretty good teams right there. But none of them are at the elite level of Texas, Florida or Alabama. Does that make the Big 10 weak?