I do hope, that we will have thorium reactors soon, but I don't completely agree with the reduced proliferation risk. In thorium reactor you would have weapon-grade uranium (isotope 233 and a hint of 232), which can be chemically isolated. Sure due to U-232 it will have radioactivity of levels, which in long term are harmful. However the levels aren't so high, that they would prohibit the handling of the material by people, who don't care about radiation safety that much and I can easily think that to be the case with nations and groups most eagerly trying to achieve a nuclear bomb.