I don't know excatly to what "unfreezing Khan" scenario refers.
A body itself has to hold information to be revived.
The Enterprise crew revived Khan without knowing he had been a war criminal in the past. The historical records on that war were incomplete and could have given them no warning of who they were reviving.
This month's media thread includes a short article on some people's idea to have Ayn Rand frozen, which ultimately didn't happen. My first reaction was a shudder. I thought, I definitely wouldn't want Ayn Rand preserved forever. My second thought was, What right do I have to say who can and who can't get frozen?
Whatever your thoughts on Ayn Rand, I think this can spark an interesting conversation: What, if anything, should humankind do about people who are widely seen as harmful for the whole? For example, if the Castro dynasty in Cuba or the Kim dynasty in North Korea decide to freeze themselves to ensure they will continue oppressing their countries forever, should that be prevented? (And yes, my opinion of Ayn Rand is such that these examples came to mind.)