I'm playing devils advocate. The crucial question here is one of TIME. If world war 2 happened 125 years ago would it be a different story? If slavery happened 50-60 years ago, would it be a different story. It's time that is the crucial issue here.
Doesn't matter if WW2 happened 2 years ago or 200 years ago, what was done by the Nazis and the Swiss banks was illegal at the time. Therefore the entities involved (i.e. people, banks, etc.) could be prosecuted now. Slavery, abhorrant though it may be, was NOT illegal at the time and that is the crux of the issue.
It would be the same situaion if in say ten years they were to make drivng petrol engine cars illegal because they are harmful to the environment. Then, 150 years in the future from then, the grandchildren of people forced to work in bad environmental conditions (smog, etc.) due to the use of those petrol engine cars sue the companies who used to make them. It's ridiculous.
Bitter, twisted and better than you.