I think if there were a strong case, this would have been tried by now. A friend of mine once did an audit (IIRC, at PSU) for Spanier. He told me that of all the audits he had done he had never had a more open and accommodating person than Spanier.
My opinion is Spanier may be the "bridge too far" target. I will always maintain that Paterno should have been the target all along. I also maintain there is a lot more to this case that just Paterno knowing.