I think that McCain at least had a strong identity to run on. Even Dole had a persona to run on. Ridge manages to be nuanced and boring, which seems to be an electorally lethal combination -- especially if you have to break out of the second tier.
But Ridge was a governor (of a large state, no less) and held one of the "sexy" cabinet positions. Again, however, I'm not sure that's the stuff people will be looking for.
Yeah, he was a member of Bush's cabinet and his most well known acheivement is the creation of that color-coding system now regarded as a joke by almost everyone. That's a real winning resume.