Of the categories voted on so far, I agree with some and disagree with others. I would have gone for Mandela in the leaders category, and Ali in the sports category was easy. For the activists, don't have a problem with MLK but might have gone for Ghandi. For scientists are, I'm with jeremyp and would have gone for Einstein. The entertainers, of the choice avaiable, Chaplin, but thought Elvis should have been in there. I am a huge Bowie fan but not sure the global impact is as wide. The explorers category is just odd, but Shackleton seems bizarre. Of the choice there, Armstrong.
The artists category, yet to be voted on seems a bit of a motley. Given a free vote, I would likely have chosen Dali. Of the four already chosen, Picasso.
When it comes to the overall head to head, which I agree with earlier posts is a nonsense, but then the whole thing is, I would hope that it will be Mandela from MLK, and would probably have Ali next