I get what your saying but I just don't think the Big Ten underachieves on basketball. They pretty consistently get multiple teams to the sweet 16, which I think is a good indicator of the strength of a conference. Anything past that is more of a commentary on the individual team because it becomes such a crap shoot from there.
Disclaimer ... I go back to Jerry Lucas, etc. at OSU.
Outside of Michigan State and perhaps Wisconsin, the Big Ten doesn't strike fear ... IMHO